Frequently, I use strict and warnings, but there are times I don't. And sometimes prototypes become production code. They get copy pasted by some mad madness. It's possible to also do my $x = @_, which will work w/ strict and warnings.

Unless I have a good reason, I prefer shifts. It's just a preference as defensive programming. 'cause one day, somehow a my $x, $y = @_, and someone will forget to use strict. And I'll be part blame for the assignment, someone else for the warnings and strictness.