Practically I am not sure if this could be done –All A/C to be assigned their own Xsponder number and this logged on installation. We would then not be given a squawk on clearance as the A/C ID number would have been entered in the FP. ATC would then be able to ID any A/C (via database)on their screen. Xsponders would then not need to be switched on or off i.e. outside of flight deck control. I also believe that cabins should have video cameras running monitored from the flight deck.