HalcyonDaze
Contributor
SCUBA divers are one thing; on most recreational dives sites unless a deep-draft cargo ship is plowing through they aren't at risk until they surface. If diving from a boat, the flag is more for the boat crew to keep track of them than to actually ward off other boaters on its own. Often in my experience trying to tow a flag at depth is more trouble than it's worth, so I'm fine with just the DM carrying one for the group and having a big DSMB for myself. Snorkelers are a different story; they will be spending most of their time on the surface or shallow and don't have the option of just hugging the bottom.
That said, it's a boat operator's responsibility to not hit things, and that includes divers, swimmers, or anything else (like say, floating debris). Providing a highly visible surface marker has to be balanced against the ease of towing it, and there's little point in dragging around giant flags, buoys the size and shape of a mini-fridge, or red-and-white windmills if boaters are still going to blatantly ignore them. [Edited by moderator]
That said, it's a boat operator's responsibility to not hit things, and that includes divers, swimmers, or anything else (like say, floating debris). Providing a highly visible surface marker has to be balanced against the ease of towing it, and there's little point in dragging around giant flags, buoys the size and shape of a mini-fridge, or red-and-white windmills if boaters are still going to blatantly ignore them. [Edited by moderator]