Usually, the people owed the debt is not the people who the loan was spent on. You aren't playing dirty back at them, you are just making someone else the victim of the monetary loss.
No, I reject this. The loan system in the US (at least) is dirty through and through, and anyone who ends up buying debt off of a major corporation is especially sleazy. And heck, if the banks get in trouble through irresponsible lending it'll be fine for them - their loss will end up coming out of all of our pockets.