I always wave when I feel it's safe, except at rallys. When headed to
Laconia or Americade i usually stop after I meet the first string of 25 or so bikes.
However if I am on the twisties, even at low speed I usually don't, because last labor Day about 15 of us were headed south on 9n in Lake George and met two bikes, woman in front and man behind. He was too busy waving and looking at us that he didn't see her slow to turn into a driveway. Well you can guess the rest. Those of us on the end of the line spent a few very nervous moments dodging bits of chrome and metal sliding across the road. I hate it when you end a great day on the bike by directing traffic around a fallen rider.