If they get there and just happen to "accidently" discover a parlour with 10 year olds offering a happy ending, those can be almost impossible to prosecute here...but if it can be shown that at least part of the trip occurred with the INTENT to engage in that sort of thing..THAT is where they get nailed. Doing things like checking prices, making appointments, mapping directions, emailing asking about scheduling or other relevant info...all adds up to show the intent for the act... (and boy, do businesses with an international aspect get angry at employees who return from jaunts abroad and call in "arrested for international child sex abuse"....it really tends to put the damper on their prospects for advancement...)