An example, AKA proof, is actually necessary when one makes an assertion in the sciences.
Firstly, examples are not proofs "in the sciences" unless they are counterexamples.
Secondly, this is misplaced pedantry. It really is quite obvious that, when you rely on metacharacters, your data had better not inadvertently include them. This is not an assertion that needs to be proven to anybody with a modicum of programming experience. AM was entirely correct on that point.
I'll agree that AM's admonition against using the feature was hyperbolic. Sometimes it is better to avoid the pitfalls of some language feature than it is to avoid the feature itself. And we are entirely capable of doing so. (As Rolf points out.)
"My two cents aren't worth a dime.";