You are missing the whole point of Taint checking. If you are positive that it is safe - why turn on -T in the first place? The point is to ensure that no gremlins get in. It is a trivial matter (most of the time) just to
the data. Perl doesn't care about the fact that a password is (or isn't) required - it just cares that you are trying to require a file that comes from a variable that comes from an external source.