I’m sure you know that a minor child is never allowed to be in a room with a doctor without a parent or a nurse present.
And to you and the other posters who have suggested that staying in hotel is no different than a sleepover or other events at school, I don’t think you are really seeing the issue clearly. There are so many more variables in hotel that you cannot control. I think because we are all normal well-adjusted people that are not pathological or evil, we find it hard to imagine the lengths that these people will go to to get access to kids. We worry about it when we need to but they spend much of their time thinking about ways to get close to kids. These guys are incredibly manipulative. Sometimes they charm the parent to gain trust and sometimes, when the relationship with the parent is shaky, they work on the child directly.
I agree with the posters who say that a close relationship with your child, teaching your child to trust their gut, to speak up immediately when something doesn’t feel right and to never ever be alone in a room somewhere with an adult that isn’t their family member is the best defense but please remember we are talking about 13-year-old girls. The adults in question are respected. The girls take direction from these coaches trainers etc. on an ongoing basis and they’re in a position of having to impress and gain approval from them. All it takes is one incident where a kid doesn’t say no quickly enough and then they can be convinced that they are now a participant, they’re part of a secret and they have something to lose from telling someone.
Sorry for my long post.