Free? Don't forget the expensive nightclubs, the expensive booze, the meals and drinks the "girls" would expect from you first and then, possibly, they
might let you shag them - or maybe they won't - maybe someone else will catch their eye and get the "free" shag. Or maybe the girls will get so drunk they just throw up in the street before saying, "Fuckit, I'm going home wiv ma girl-friends", leaving you to wank alone in your hotel room. Perhaps those lads have experienced that already then met someone in the pub back home who asked them "Why bother with all that crap when you can just fly to Thailand and do it in a more pleasant and more orderly fashion and with a 99% success rate at half the cost?"
Maybe, maybe not.