Fortunatelly your evil ML plan going to fail on #1. It's basically impossible to get some cash loaded to prepaid cards anywhere. Also AWS and other hosting providers wouldn't accept prepaid cards either. Instead you just buy crypto with cash P2P and report that as mined or whatever.

On other hand credit card fraud is real problem especially due to fact that Amazon don't want to add any KYC burden on their customers or try to track down any anomaly spending. After all good chunk of AWS profits come out of fact how bad people of tracking their cloud costs.

If Amazon to implement built-in option to track suspicious jumps of AWS costs then it's not only gonna cut on fraud, but on overall AWS profits.