When I'm playing as the gunner of my team in Harm's Way, a free XBLA title, I routinely get a notification on my screen that says:
Your Driver Needs Help!
What kind of trouble is my driver in? Is he under fire? Or has he merely been bumped? Gone off the track? Maybe just fallen back a position in the race? Knowing what triggers these notifications would make it much easier to 'help' my driver.