She needs them, like most Faunus

Harriet Bree was currently on patrol with the rest of the Ace Operatives. Their job was to provide security at a very importance peace conference between all of the major leaders in Remnant. Harriet was so focused on making sure nobody was harmed that she didn't notice one of her teammates sticking her finger in the back of her romper, which had some snaps on it.

This caused Harriet to jump in surprise. "Come on, Elm! What did I say about randomly checking my diaper without asking?!" She hissed. This kind of incontinence was something that was common in almost all Faunus, so Harriet had been in diapers her whole life. Against all odds, she managed to become one of the most elite Huntresses in all of Atlas, though still had issues needing diapers. At least she had seniority compared to Marrow, who seemed to be the subject of a lot more jokes, but then there was Elm, who really liked treating her like she was just some baby bunny.