No. What it is supposed to do is to run the script and die if the script attempts to do anything dangerous with not validated input. The "This is an error because, by the time Perl discovers a -T in a script, it's too late to properly taint everything from the environment. So Perl gives up." in perldiag seems to suggest that this is an implementation issue rather than a deliberate decision. Which is a shame. It would make a lot of things much easier.