I'm thinking he pushed the unlock button twice. If I press mine twice at just the right time (to unlock the passenger door), my parking lights will flash three times. The reason being is that it NORMALLY flashes twice when you press the unlock button. If you press it a second time before the second flash, it will only blink two more times, for a total of three.

That's my guess... Was your passenger door unlocked when you unlocked it and saw three blinks?

 

One flash for lock and 2 for unlock. I even locked myself in the car and then unlocked and opened the door (manually) then closed the door. Unlocked the car with the remote and only 2 flashes. I must have hit the unlock twice by accident, though I can't get it to do 3 flashes even hitting unlock multiple times.