Remember the little girl in Salt Lake who hid under her bed for HOURS after her sister was kidnapped. Kids can get extremely compliant when they're terrified.
Personally, I need to remind my kids of the intruder rule when I get home (we haven't discussed it in a couple of years). My kids know that if someone comes into the house they are to RUN and SCREAM. If they can't do one, do the other no matter WHAT the intruder says. They know that it only takes one scream to get dad to come running, and that I've shot intruders before (long, painful story).
Of course, if someone were going after my kids, my wife would probably beat me to them (and though it pains me to admit it, she's a better shot than me).
I think that kids become hypercompliant because their attacker threatens their parents "Scream and I'll kill your Mommy."
What you are doing is the best thing in the world "Scream and Daddy will come save you." :)