Is there any fail-safe law out there that catches all loopholes in existing laws?
Namely: Create a shitty business model that depends on treating your customers like shit and you can expect to out of business as soon as your venture funds dry up.
This is the sort of problem that solves itself.
Either that or people can keep giving these jokers money, wait for some lawsuit to happen and then in 7 or 8 years after the lawyers take their cut you can expect a check in the mail for 4 or 5 dollars.
Unfortunately it doesn't. If you've ever watched the UK TV series "Watchdog" you'll see time after time people set up businesses, rip people off, go bankrupt, rinse and repeat. Game theory trumps economic models here - and the rules of the game are whatever loopholes these people can find.
To be fair these cinema clowns haven't done anything much worse than a 'fair usage policy' on a mobile phone offering 'unlimited calls' would do. They were sly about it rather than upfront. They could have just introduced new terms as of the next payment. But the general point is about the free market sorting this sort of thing out doesn't work.
That's the principle why the "letter of the law" needs to be followed, not the "spirit of the law" which isn't actually defined. (E.g. a legislature can pass a law but each representative could be voting for it for a different "spirit" or intention, while the wording is the same.)
Should there be a catchall law that criminalizes unspecified bad behavior? No. But there are a few.