Yeah, that's a lesson you only learn once. I keep a cheap test bar in my box just for that. Chuck it up, sweep the indicator, and you know in thirty seconds if a holder is junk. Found a shrink fit once that was out far enough to ruin a finish pass on stainless. Now it's just part of the setup, like wiping down the vise.

Security theater" is exactly what my old captain called it too.

Nah @shane_williams, my screen always ends up covered in flour or sauce.