Yes, duh!

Jaune decided he would collar the entire team of RWBY, then decide which of the girls he would keep. So with that in mind...

He quickly placed a collar around Ruby's neck. Ruby turned, then knet in front of him.

"Master," she said humbly, not looking up at Jaune as a sign of respect and reverence. "How may I serve you?"

Jaune read her collar. "Slavegirl", eh? Interesting...