It's not a bad idea, but it is improbable based on the ways I've seen training handled. I've wanted the same deterrent for a long time, for the same reasons. Granted, my schutzund-related experience is limited to spectatorship and videos, but from the few visits to clubs I've made the dogs are focused on the person with The Sleeve, and the vocalization comes from intense drive to obtain said Sleeve. John T Smith out there in the wild blue yonder is not likely to be walking about attempting to lure in vulnerable ladies with a full bite sleeve on... although that sure would make it easier to identify potential creepers!
That said, there are very likely to be other ways to train than the limited methods I've been seeing. I'm riding your coattails here to see for myself what shenanigans my crew and I can get up to. I doubt a dog without much drive would care enough to put on a good show either way, though.