Understood, but the concept is the same, and emphasizes your point about the "safeguard"... you have to consciously (or subconsciously) rack the slide, which can signal that something is wrong if you're paying attention. I've personally never seen or heard of a squib that cycled a semi-auto correctly. I imagine it's theoretically possible, maybe in a long-barreled .22 rifle or something.
This is why the "tap-rack-bang" drill is good for combat and possibly competition, but you are taking a little chance every time you do it. I've seen a competitor tap/rack/attempt three times before the RO stopped him and we checked the bore... luckily the squib bullet was still far enough back in the barrel to prevent the full chambering of the next round/s and kept it far enough out of battery. Gun show reloads. SMH
I also have an (inherited) single-shot .22 rifle with at least 4 bullets squibbed into the (now ruined/bulged) bore. "Hmmm... that's weird." (reloads, fires another). "Hmmm..."