do you jiggle the knob?
if you're waiting for the bathroom and the door is closed. it could be:
- closed and locked and occupied
- closed and unlocked and occupied (possible horror scenario)
- closed and unlocked and unoccupied
(but hopefully not closed and locked and unoccupied!)
do YOU take your chances, and jiggle the knob so they know someone is waiting. how long do you wait before YOU jiggle the knob? some places closed signifies occupied, but some people close the door all the time so YOU have to jiggle the knob.
"I take what is mine. I pay the iron price."