This is something I've wondered as well. How would we punish excessive bad reports?

Moderators have a ban reporter button. If you find a series of reports that are a problem, come tell a moderator to ban the reporter. Removing the report removes the way to ban them, though.

This is somewhat on topic: There's at least one person in /a/ who consistently reports EVERY instance of "battletoads," "combat frogs," and similar responses to source requests.

Granted, replying with "battletoads" is pretty stupid, but I generally clear the reports because people realize it's a joke. But there are 3-4 reports a day for "battletoads," and assuming that I'm doing the right thing by clearing them, it would be nice to warn the guy and say "hey, stop reporting this."