Objectively, people are irrational about probabilities. Study after study shows that you can give people probabilities and ask them for decisions, and they will usually be wrong.
People are also incapable of understanding the legalese they're signing (that includes privacy policies as well).
Without actual understanding the substance or form, in theory there is no actual agreement, and thus no contract waiver of liability. (No theory of private ordering is predicated on duping people because that world only produces fraudsters.)
So this comes down to burden of proof: courts assume that if you're legally competent, you can sign away anything. There are very limited situations with strong evidentiary requirements for getting out of it. There's nothing socially beneficial about this assumption. It just makes contract law easier to administer.
In terms of regulation, there's no clear mandate for NTSB, the FAA, the county or the state. Indeed, the incentive is to ignore it: why spend a ton now to maybe save some indefinite person in the future?
Only the professional organizations - the medical lobby, the parachutist whatever - want to do (only) what's needed to keep business going, but that's not enough, and it's a strong incentive to hide problems.
Add to that lack of any personal honor (of being a responsible pilot or trainer or practitioner) in fields undertaking as any job in a backwards economy.
So: no regulation, no law, no private standards or personal honor will prevent excited customers from making this mistake, and some business person will engage in enough denial to make money off them.
At a minimum, neither waivers nor limited liability should not be available for gross negligence as a matter of law, and any form contract should be construed against the writer. Making this consistent and clear across all jurisdictions would root out most abuse without affecting responsible businesses.