It could have been worse.

6. People should not be ashamed of how they look like when they are in or around water.

With a bit of hesitation, Rob clicks to confirm. The green light flashes and he sees the new rule pop up on the app, below the ones he'd already created:

1. THE APP „ABSOLUTE RULES“ ALWAYS SHOWS INSTRUCTIONS ON HOW TO USE IT.
2. WHENEVER AN ABSOLUTE RULE TAKES EFFECT, A GREEN LIGHT FLASHES AT THE TOP RIGHT CORNER OF THE SCREEN.
3. APP CREATOR AILEEN IS ALLOWED TO FELLATE A HUMAN PENIS.
4. APP CREATOR AILEEN IS ALWAYS VISIBLY SHOWN ON THE APP „ABSOLUTE RULES“.
5. APP CREATOR AILEEN IS ABLE TO TALK LIKE A HUMAN BEING THAT IS SIMILAR TO APP USER ROBERT LAURENT.
6. HUMANS EXPERIENCE NO SHAME RELATED TO THEIR STATE OF DRESS WHEN THEY ARE IN OR NEAR WATER.

Rob raises an eyebrow. The way that his sentence was interpreted by the app is a bit weird. It seemed to focus more on Rob's current feelings about sweaty clothing and less about what he really intended, which was to just remove shame related to one's appearance.
In general, Rob is happy with this rule. The fact that it only seems affect the state of dress for people instead of their appearance in general, is an even less invasive change than the behaviour of others. Maybe this was more along the lines of how he could make the world a better place.
Bit by bit, instead of trying to end war and famine with a single rule.

Before he could really start to look around for what his rule actually did, his phone buzzes again. Almost automatically at this point, he opens Aileen's interface.

A.I.: good rule! picked a bigger one to start with after all, didn't you?

Rob furrows his brow, suddenly unsure about his choice.

Rob: How do you mean that? I think people shouldn't feel uncomfortable in their swimwear! Doesn't seem like that big of a rule to me...

A.I.: true, and I like the rule! ... but you basically just destroyed all bathing wear business I think. I don't know though, I just felt the rule pop up. I'm just chilling in your living room, hacking your laptop.

Rob: WHAT? Stay away from my laptop! Anyways, I didn't think about it that way. I'll just walk around and see what has changed. Might head down to the beach for a bigger picture.

A.I.: yup, sounds like a plan! lemmie know if you need any pointers. I'm so bored I might just go and suck a dick somewhere.

Rob: What are you and what the fuck is my life.

A.I.: changing, dude. your life is changing.

Rob sighs and puts his phone away.
He walks through the park for a while, looking around. It doesn't seem like much has changed. The kids by the fountain are still the same. There's a grandpa playing with one of the children. He wasn't there before and his clothes are completely drenched by the water, but that's nothing too weird. He might've not cared about that before the rule either.

Rob decides to head to the beach. There is a fairly well known sea side promenade in his town. He usually tried to avoid it because it's a bit of a tourist trap, but it definitely would be the best place to see what his test rule had done.

The impact of his rule went way deeper than he could've ever imagined.

When Rob arrives at the beach, he's dumbstruck at how different it looks. The promenade seems to be largely the same, but there are a lot of stores and vendors he couldn't remember from his past trips here. What makes the difference so jarring however, is the way that the people, that populate the beach now look like.

People dress a lot differently to how he remembers. There are a lot more varried and individualized styles around.
Everyone seems to dress according to their own preference and comfortability.

He sees an older couple wearing long sleeved, striped full body suits. They were clearly made to be worn in water. He also sees a whole bunch of children in similar type of full body swim wear.
It occurs to Rob that, since people no longer experience shame regarding their clothing, style wasn't even a question. One could look as stupid as they wanted to, people simply didn't care anymore. So these types of full-body swim wear probably came from a place of concern, focused on protecting the skin from the intense summer sun.

Rob smiles to himself. „Ha! This means that I did, in fact, not kill the business of a whole clothing type.“

One thing that his rule had not changed is that personal interest in style and fashion is still very varied from person to person.
Rob spots a lot of people in very extravagant bathing suits, often fairly revealing. It's bikini's and shorts, but every single piece seems unique and personalized to each individual. The styles of the various bathing suits clearly aim more to serve looks, rather than protection or coverage.

No matter how much Rob tries his best to note all these positive things that his rule had changed, he keeps getting hung up the most obvious change:
Over half of the people at the beach are simply butt naked.

Rob catches himself staring on more than one occation. It's an obvious result of his rule, now that he is able to see it.
If people don't feel shame about their state of dress around water, they can just drop their clothes and go for a swim!
No reason to spend money on specified swim wear if they don't feel ashamed being naked around water.

Embarrassingly, Rob's pants form a tent at this thought. As the only human with a memory of how things were before his rule took effect, he's also the only one that was caught off guard by all the naked people.

Rob also notices that he doesn't seem to be the only person walking around with an erection. He sees more than one man sitting with a towel or bag covering their hips, more than one woman idly pressing their legs together, watching from afar. It gives Rob some relief that he at least isn't the only person affected by all the attractive people prancing around naked.

One woman in particular catches his eye. She isn't fully naked, she's wearing a colourfully striped bikini top with a fake flower attatched to it. The top is like an elastic band around her chest, only does it not cover her tits. Instead, it's strapped over top of them, wrapping over her chest and underneath her arms to connect at the back. It's clearly just meant to catch the eye and show of her rather large and pretty bust in a fashionable way. She's also wearing a matching piece without any flower on her lower half. Almost like a belt. It sits fairly low on her hips, just high enough to not cover a well trimmed patch of hair above her exposed pussy.

Rob stares from his bench with a throbbing cock. The woman is sunbathing on a reclined chair and hasn't noticed him staring. If she has, she doesn't care.
He clearly also isn't the only one stealing glances, but people don't seem to care too much. After all, these people have never known differently.

Rob's mind goes through several stages of thoughts as he tries to focus back on the task at hand.
He's surprised and scared by the extent of the changes a single rule had caused.
He's also very aroused at this point and tempted to experiment with the rules more in that direction.
Then it dawns on Rob that this rule he just made is, in fact, permanent now. This is just how people have always behaved around water and they will continue to behave this way in the future, unless he influences this rule with a newer additional rule.

With a flushed face and racing thoughts he takes out his phone.

Author's note:

This is a great place to split the story in different directions.

I have a Companion Path planned that focuses more on Aileen and her place in the world, as well as a few initial ideas for a more careless and classic Free-Use branch.
If anyone wants to add their own chapters, please feel free to do so here, or at any other point in the story.

Thanks for all the great feedback so far!
Let's see what Rob does next!