I read yours after posting this and it provides exactly zero information:

> I promise, you are not the first person to have thought of this, and, believe it or not, there are reasons other than malice and avarice that cloud providers don't terminate service based on billing caps. Terminating service is a big deal.

"Terminating service is a big deal" how? I can explicitly cancel a subscription after a certain date—what is the problem with me explicitly cancelling a subscription after a certain amount of spend?

No one is asking for automatic circuit breakers applied to all customers indiscriminately, but I'm not seeing any justification in here for why an opt-in circuit breaker is technically or legally challenging to implement.