Cop gets warrant to search a suspects mailbox. In the course of searching the mailbox he decides to burn down the house and jackhammer the foundation of the house looking for the body of jimmy Hoffa. Does anyone think this is the sort of behavior you should be rewarding in police officers regardless of what he finds? If you don’t exclude the evidence how exactly do you discourage the behavior?
Wll, I could make him pay restitution.
Plus, since his warrant didn’t cover any of that stuff, he wasn’t acting as a cop when he did it. So everything he did was a crime (destruction of property, arson, etc), so I could charge him with those crimes.
In your ridiculously extreme example, it isn’t hard to find ways to punish him that aren’t excluding the evidence.
The point is rather that there should be NO reward. When it comes to search and seizure, we don’t care if the cop is willing to trade his career and freedom for the chance to search for evidence.