For what it's worth, I've NEVER flown/jumpseated with someone making any of the 121.5 "comments" or "sounds" at the regional, LCC, or Legacy level. Obviously, it's a daily occurrence. Florida is almost always silent. I agree with the previous post that once you get up in the ATL area, it starts to kick off and once in the northeast corridor, all bets are off, it's continuous. I assume it's *mostly* regional guys just based off of the locations where it is and ISN'T happening. This should be crossposted in the "Regional" forum. I don't see anything wrong with a quick "you're on 121.5" if it's the 3rd mistaken transmission or so to help the other person out, especially if it's a GA guy making traffic calls, but the back and forth play and even the guys that try to lecture on the frequency is definitely getting old.