From ITF RULES OF TENNIS
26. HINDRANCE (OLD 21,25 & 36)
Case 4: During a point, a ball or other object that was lying on the player’s
side of the net when the point started hinders the player. Is this a hindrance?
Right you are 10is champ. I like to refer to them as landmines.
This is my evil side typing: If a loose ball is in my opponets side, I would attempt to hit near that ball and that may result in a couple of things.
1) my opponent will be distracted in trying to avoid it.
2) he steps on the loose ball and.... well use your imagination.