I know an elder who never does any physical excercise all year (except during Field Circus, which shouldn't count since everyone is now walking at a "pioneer's pace"). During Christmas week, however, he goes for these long walks with his wife in different nearby neighborhoods making sure to walk near all the "inactive" JW's homes...
I later found out that he does this every year to see if any inactive JWs have put up Christmas decorations or if their kids are playing with new toys outside, etc.. This elder doesn't see anything wrong with doing this as he believes he's doing his part in keeping the congregation clean... really strange character...