Comment by overfeed

Unless the surveillance is total and the technology flawless and unbreakable, this scheme is a bet against human ingenuity, and can be neutralized given enough time, creativity or unforeseen loopholes. Off the top of my head, a conspiracy among the help to act as a mutual dead man's switch will stale-mate explosive collars: if one conspirator is killed, junior will get dispatched by an unnamed co-conspirator.