Well, right. Fast and Furious was a "sting" that just let contraband guns be taken into Mexico. Nobody was arrested in the the "sting" and now the cartels are more heavily armed than they were before...yay!

It was run by Eric Holder, hence my joke about not arresting anyone being a sting run by eric holder.

Assuming you actually are trying to enforce the law, the mark is arrested during a sting or immediately after. You dont let them escape w the goods. That is a botched sting, at best, or intentionally giving contraband to criminals, at worst.