In the real world how many people buy subscriptions to multiple porn sites (monthly renewing) in 1 1/2 hours?

For us, we sell cam credits where a minimal package might last 30 minutes. So, a repurchase might occur in less than an hour making the scenario you present an major issue for us.

This is one reason why we prefer not to use 3rd party billers -- we process through our bank direct in most cases.