That doesn't mean you couldn't have a service which by default has no hard cap, and people have to opt into it. You could even put a user interface thing where people have to type a whole sentence perfectly matching and hit OK, like "I understand that enabling a hard billing cap will shut off services if it exceeds my monthly quota". Wrap it in as much service agreement contract, TOS language as is necessary.

Heck, have it do the equivalent of send people a DocuSign equivalent PDF to sign acknowledging the risk before enabling it. Would it still stop pissed off people? Probably not. Would it help with the risk of lawsuits, very possibly.