I am a little bit surprised by the lack of depth in discussing such a major product change.

I get it, the problem is definitely worth solving for. Waking up with a $100k bill isn’t great.

At the same time, from a product perspective the proposed solution might be a bad idea. Simply having hard caps as default will definitely turn out to be as bad for some people as a $100k bill, see for example (1).

You can’t come up with good product changes if you don’t discuss the potential negative effects of a change.

(1) https://news.ycombinator.com/item?id=49950196

Then add the option, but make it default to soft caps. Or bake the default into the tiers. If I sub with a $20 spending limit, I will probably be ruined by a $2000 bill. On the other hand, if a company subs with a $1000 limit, it can probably cover the occasional $10000.

At the very least, there should be an optional hard limit that is obviously indicated in the UI. When you're signing up where you set your "usage cap" warning, next to it should be an optional hard cap with big bold red letters "THIS WILL CUT YOU OFF THE MOMENT YOU GO ONE CENT OVER". So I can set e.g. a warning at $20 and a hard cap of $100.