One of our club members flies with the 1st Gen Stratus and iPad mini. It works to see the airliners descending into the local class B.
It's a carry over from his powered aircraft. And if he's close enough for the airliner to be an issue, he's within the hockey puck airspace to piggyback on the TIS-B data being broadcast to the airliner. So the airliner sees the glider 1202 code.

BillT