Okay I suppose that makes sense. I've been with groups where some of the more brash have gone off and covorted in the bathrooms, and when the establishment has a problem it has never been a big deal. I still can't envision managers actually calling the parents on them.
also they might be getting repeated business through this "new" client called grouper and then notice some of those people having sec in the bathroom. It's probably more than a one time thing so they realize it's a business and then don't want to get associated with certain kinds of businesses which the law is really hard on. It's illegal to make profit from or take any more from money made from prostitution so it's in their interest to make sure everything ok and they aren't being turned into some poorman's brothel and don't have to worry about the cops shutting them down next week.
That's because if you guys just show up at the establishment, they have no idea who your "parents" are or where to contact them. If, however, your group arrived there through some arrangement (between grouper and the establishment in this case), they do have a place to complain if you do something they don't approve of.