you turn warnings on in places where the original coder might have specifically omitted them.

Did the original coder bother to local §^W = 0; or no warnings qw(whichever); ? If not, then I refuse to assume they specifically omitted warnings because they didn't. Code should always be made to run silently in the presence of enabled warnings; that doesn't necessitate "fixing" the cause of the warning, but it does necessitate being aware of a violation and disabling warnings as needed. -w is not harmful. People who don't anticipate it are.

Makeshifts last the longest.