Ah, that's a useful example, thanks.

Update: now that it's been sitting in the back of my head for a while, however, I think I'd always immediately undefine the unused variables after acquiring them anyway, to make it clear at the top of the subroutine that it doesn't implement anything that uses those arguments. That would still clear the warning. The only time this is probably a bad idea is when a lot of arguments are being passed but not used — but then you should arguably be passing an object or hashref.