Yes and no. 100% accurate billing is not available in realtime, so it's entirely possible that you have reached and exceeded your cap by the time it has been detected.
Having said that, within AWS there are the concepts of "budget" and "budget action" whereby you can modify an IAM role to deny costly actions. When I was doing AWS consulting, I had a customer who was concerned about Bedrock costs, and it was trivial to set this up with Terraform. The biggest PITA is that it takes like 48-72 hours for all the prerequisites to be available (cost data, cost allocation tags, and an actual budget each can take 24 hours)
The circuit breaker doesn’t need to be 100% accurate. The detection just needs to be quick enough that the excess operating cost incurred by the delay is negligible for Amazon. That shouldn’t really be rocket science.
We're talking about a $2.5T company. Literally every example in this thread is already negligible to Amazon already without circuit breakers.
Implementing that functionality across AWS would cost orders of magnitude more than just simply refunding random $100k charges.
The point is that by not implementing such configurable caps, they are not being customer friendly, and the argument that it couldn’t be made 100% accurate is just a very poor excuse.
Sure, not providing that customer-friendly feature bestows them higher profits, but that’s exactly the criticism.
They also refuse refunds. Because it is profitable, even if the customer is unhappy to pay it.
If it were highly profitable for them to implement some form of budget cap cutoffs, they would! It's obvious it's not a game they are interested in.
What about 90% accurate?