User blog comment:Ian Jones280224/Radar visibility/@comment-1265875-20120202235105

There's actually a bit of info on this in the Free Roam article, but ultimately it depends on what game mode you're in.

In Normal and Friendly Free Roam you show up on the minimap at all times unless you've just respawned, but that only last about 5 seconds before you re-appear.

In the Expert and Hardcore Free Roam modes, you will drop off the mini-map when you are not pressing A (X on PS3) or are crouched. Also in these modes you can set it so that your name and motto do not appear over your head.

Free for All and Gang Match modes work similarly to Expert and Hardcore Free Roam with the exception that you can't remove your name and motto unless you are playing in the Expert or Hardcore versions of these modes.

Hope this helps.