But the NACD says to use a personal marker pointing at the emergency exit, not pointing towards the route the divers want to do, which can be different if all things are well. So arrows, fastest way out, other markers can point to a specific path a diver wants to take.
And when other books recognize the possible problem of using arrows with personal meanings, I think it's logical to try to avoid ambiguity as much as possible.
But it's interesting to see that there are different positions about this. I wasn't aware.
Isn't it though?
More interesting data..
"The Art of Safe Cave Diving" - NACD, 1995, page 89:
NACD BOOK:Types of markers that have been employed during the past three decades are clothespins, outrigger clips, and plastic arrow markers. Markers should always be placed on the EXIT side of the permanent line. But remember, NO directional marker is fail-safe.
and
"NSS Cave Diving Manual: An Overview" -NSSCDS, 1992, page 91:
NSSCDS BOOK:Clothes pins are a must at jumps, especially jumps made from points at which no permanent marker has been installed. Placed on the outbound side of the jump, they confirm exit direction as divers return to the jump. Even when permanent markers are available, clothes pins provide a personalized touch to help reconfirm direction of travel.
Note, when both books were written cookies did not exist, but Wilson line arrows (aka "permanent markers") did.
So, yes, it seems there is a lot of disagreement on the best way to mark jumps, but I think there are compelling reasons to use cookies to mark YOUR exit so that you do not contradict arrows and potentially confuse other divers.