That wouldn't change anything in this case. Either way you would need to (a) be able to know the state of billing in band before executing a request or (b) accept a slight out of band delay where cloudflare may allow a few extra requests through and eat the cost.
It is a very solvable problem, I just don't think pre- vs postpaid changes it.
It is a very solvable problem, I just don't think pre- vs postpaid changes it.