Fish, only slots have this rule because it is a trade-off for not putting out on the machine what the percentage is. That was determined many decades ago when slots went to the Telnaes method. I won't go into explaining it, but it essentially makes slot odds impossible to determine without knowing how exactly they are programmed. This isn't the case with any other game. You can figure the odds with mathematical calculation and an understanding of the particular rules for the game. What is not fair about sports betting when a bettor can figure out the true odds and still chooses to try to beat them? That is Las Vegas and all gambling. Businesses that have an edge and the world knows it, but people still play. Nothing unfair about that at all.
I can see your argument for minimum payouts for sports books, but the problem is the people want to play the pie-in-the-sky parlays and no one wants to be in a spot where they are telling customers no. In your scenario most books wouldn't offer more than 5 or 6 team parlays. Suckers love 10 teamers, but books aren't going to let them have a shot at them if they have to pay out say 75% on these bets. So either you tell people they can't play them or you just shake your head at them and thank them for helping make sports betting a potentially profitable game for a handful of people.
As for the GCB's rules, we should all be fair in judgement of them. Who in the Black Book is barred from casinos? Almost all of them are convicted cheats and people with clearly known mob connections. They don't bar counters or anyone following the laws including bonus machine players, those decisions are left to the casinos. Private businesses are always allowed to refuse the right to visit from anyone, as long as it isn't done for racial or other prejudiced purposes.
