…not providing one isn't really cause for a berating, particularly on fundamental points…

This was my original request–

Perhaps you could show how such a legacy code trap might work. Some code to demonstrate the issue.

It's cromulent and it would have taken less effort to demonstrate for someone who knows any Perl than to go on and on about how it's clear to everyone. And regarding particularly on fundamental points, just no. Flat Earth is a thing. Complete disbelief in evolution is a thing. And hackers who put passwords in query strings or cookies, can't understand the most basic properties of numbers or data structures, and cause multi-million dollar breaches of data are most definitely a thing. As I said, if you or pretty much any named monk here had done the post, I wouldn't have objected, except perhaps to say, as you said, the urgency was hyperbolic. Twenty years in mostly on legacy Perl I never saw the problem once. As LanX said, there is some context lacking and probably I'm overly aggressive with the situation—syphilis recently called me out on it and was quite right—but I'm 100% done with that monk or anyone unidentifiable who sounds like him.