But it doesn't prevent me from being human and making a mistake.

Ok, firstly, you said that you can't easily do what you wanted, not that it was easy to make a mistake.

Secondly, attempting my $x, $y = @_ with strict in place (which is best practice anyhow) produces:

Global symbol "$y" requires explicit package name
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Which would be a pretty big clue to me that something was wrong (you aren't creating a lexical $y with my $x, $y). Doing the same thing with warnings turned on (another best practice) results in:

Parentheses missing around "my" list
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I'd say that pretty well prevents you from making this mistake, anyhow.