I have a 4/3 Narval Dion Agius (and 3/2). A shark will think to themselves "I don't like the look of that stripey arm" and leave me alone....
The other thing in midpoint of mind (not back not front but kinda there) is shark factor.
A couple of years ago the Shark Shield product was starting to gain some market traction in Vic - battery in tailpad and electrode sticker along the stringer on the underneath of the board. I spoke to a couple of users of these and both said they do get accidentally shocked when grappling with the board during heavy duckdives and wipeouts.. I haven't seen anyone use one for a while.