Unsympathetic Defendants Often Make Bad Case Law

Here's a case where it did not.  Comm. of Penn. v. Ford (Penn.Sup.Ct. 2016):

Appellant claims the trial court erred in denying his motion to suppress the firearm seized from his home. He also argues that the trial court erred in finding the evidence sufficient to sustain his conviction for possession of a firearm with an altered manufacturer’s number, because the manufacturer’s number was merely obscured by corrosion, not by human hands.

Ford was a prohibited person (not lawful to possess gun).  Rust is not a crime.