So, out of $11k, they make $1k. That's the kind of money they need to make between once and three times a month minimum depending on where they live. Doesn't Amazon notice patterns in terms of source, scripts which are uploaded and scaling profile: Who uses 2 medium instances for a year then spins off 2,000 in 20 minutes?
Certainly there's a pattern there, but it's not THAT far away from people who intermittantly scale stuff for short bursts of huge processing. False positives in those cases for people that really intended to spend $10-50k in a short time might mean a HUGE loss of revenue and/or incurred customer support and service costs.
