We have looked into this before. Hotels (most if not all) do use babysitting agencies and the sitters are checked out properly. I would also assume that the babysitters have previous experience with the hotel, its guidelines etc so the babysitter would know what they are getting themselves in for.

Why dont you give the hotel a call and have a chat to them about the situation?

We've never used one though.. Always plan to, but never get the chance to. A