Every time...

...I hear about someone experiencing a negative outcome in the form of a mistaken identity shooting in the home, I think about this picture, the concept for which I stole blatantly from Claude Werner:

(Alternatively, you could call out "Who's there?")

And don't give me that nonsense about "giving away your position", we're not laying ambushes on the Ho Chi Minh Trail, Rambo; we're trying to discern what or who is making the bump in the night down the hall.
.