Yeah, all the Brits who moves to Thailand or lives here, knows the rules. Fair or unfair, has nothing to do with it. If they make a choice to move to Thailand, they will also make a choice to go by the rules. Break them, and sooner or later you will have to pay for it. Something that might be so hard that they can not stay in Thailand no more.
Welcome to Thailand! Stop hiding and breaking the law. If you can´t afford it, Thailand is not for you. Then it´s better to chose a country where can get your full pension.