Depth and ID detection are simply electronic best guesses ,,,,F75 even has a "confidence meter" to give you an idea how sure the circuitry is that it is telling you the truth. So sure, would be simple for a manufacturer to program an option/setting to simply not alert on what it thinks are coins at what it thinks is less than 4".
Outside of the fact that I have found the majority of silver I have found 4" or less with an Ace 250, if I had that feature I wouldn't want to use it except out of occasional curiosity. Imagine the things you'd be passing over, trash yes clad yes and who knows what else.
Really, I guess that concept is the opposite of the "dig everything" crowd, "dig very little" ... And we know what the tally would be between those 2.