Yes. If you take the time to find out who the intruder is, you might be the one who gets shot first.
Yes, and if you shoot blindly at a noise you could give away your position and draw fire. Moreover blasting away in the dark endangers other occupants of the building as well as neighbors.
The right to arm ones self isn't all manly shoulder-swinging and fun. Keeping a gun carries with it great responsability. The first responsability of packing heat is KNOW WHAT YOU ARE SHOOTING AT.