RobertS, no need for concern it is all well thought out. IIRC from my line days of many moons ago and for the B747-300 the flights locks (door locks) were activated at 80 Kts and deactivated at slightly more or less, so it is speed that activates the locks and not as you rightly say squat switches, sorry can't for the life of me remember were the speed signal comes from but either ASI or ADC.