Unless things have changed in the past few weeks, we go to "TA Only" in the KC-135 for Refueling ops. Still get traffic calls on the reciever if he moves around too much!

Also, going into EWR a few years back I had a TCAS target displayed 1000 ft below me. Center tells us about a GA aircraft at our 2 o'clock and assigned 9000. I happen to look out the FO's side window in time to read the guys "Sporty's" hat as he blew by about 200 ft below us. When I told center they queried the guy. His answer was that he was a little off altitude and had an old altimeter setting. Luckily I learned about this limitation the easy way!