A lot of example code (e.g. CPAN module's doc), for the sake of being brief avoid the use of strict.

But even if the example code does not have use strict; and does not declare variables (e.g. my $xyz;), you should. Regarding the few exceptions where strict should **locally** be disabled because you want to do some hackery, then by all means zap the bastard as if it was a star-wars rogue (barhards? plenials? prole-lians? obviously not acquainted with the subject).