It's rare but it does happen. Only stumbled across it once in all my years of punting.
I got in the room, chatted with the escort for a bit and then requested a shower. She proceeds to knock on the bathroom door, opened it slightly and started talking to the person inside. I could see another woman sitting in the toilet with a fecking laptop. They were talking in another language so I couldn't understand but I guess she was telling her friend to leave the bathroom for a bit so I could take a shower lol
Took my shower, her friend went back inside the bathroom and we got down to business. It was an odd experience, but at least I get to tick that one off the bucket list