|Quoting Kimon (Reply 2):|
Interesting; I hadn't seen this before. What they're proposing is the airport equivalent of traffic lights + redlight cameras. The treadle they're talking about is a pressure-sensitive device that detects when an aircraft rolls over it; if an aircraft has been cleared to cross it, everything proceeds normally. If nobody's been cleared to cross it, it squeals an alarm over VHF so "everyone" knows that somebody isn't where they're supposed to be.
I can think of lots of potential logistical problems with implementation, but none are insurmountable.