In almost every episode someone has to pick a lock. They insert the pick, wiggle it a few times and open the door. To actually open a lock you must also rotate the cylinder just as you do with a key. For this you would use a second "L" or "Z" shaped pick to exert pressure while you moved the pins with the first pick. This is never done.
In numerous episodes a very tiny black "tape player" is used. It is identifiable by the aluminum tape reels which each have three holes. This was a dummy prop and, in several shots, it is obvious that the tape is a continuous loop running around both reels since the shiny aluminum center of the "takeup" reel is visible rather than the brown tape color.