Not at all. If you don't use it, how could you know?
I use the Assisted Plotting mod. Sonar tracks still appear on the map, but visual contacts only appear as dotted circles, and then only if the cursor moves over them, and then they only say 'Unknown'. If you lock on and identify it, or the Weapons Officer does it for you, then that contact and that contact only shows up with the information. That way they're plotting only what you give them, as in real life.
http://www.subsim.com/radioroom/down...o=file&id=1328