Most schools make very little from "trial lessons", but I can't agree with you Fuji that we in the industry are doing anything against the law.
A punter walks in and wants to fly. If you ask them wht they want to do and they say "I just want to take some aerial photos" and aren't interested in anything else, then that would be dodgy. He learnt nothing.
However, someone who has been bought a lesson for their birthday, turns up, is briefed and then is given every opportunity to "have a go" whilst having the aircraft explained to them. EVen if they don't ouch the controls once, they leave with more knowledge of aviation than they arrived with.
That is an air experience flight and as I mentioned, until the content of that flight is defined, then noone is breaking the rules unless they are obviously imitating an AOC flight.
A "pleasure flight" doesn't allow anyone to have a go on the controls or have any explanations of how it all works. Ex 3 whilst not having anything laid down, does tend to push the idea that some form of learning goes on.