Holy sh#t touchy subject ey, love it. I support both sides of the coin, I'm not guna buy 1 cause they zap me when ever I'm near them and would rather spend the money on better fins or another new gun. 2 years ago while out on the reef on a deep drop off I was 10m down untangling a big trout from the reef when from behind something pushed hard into the reef edge, I looked around and was staring a 5m Tiger (not exagerating 2 witness's) in the face, as brave as I could (nearly died of heart failure) I took off for the surface in total fear. my quick movement actually scared the sh*t out of the shark as much as he scared me. So here I was on a reef edge that was 40m deep gun still tangled 10m down and this shark came back for another look, This time I was able to remain calm as it had not surprised me and it just swam away slowly and we didnt see it again. The shark shield was not needed but I def wouldn't have a prob with 1 being there to stop that happening in the 1st place. The big tigers up this way dont actually scare me but all the dumb ass bull sharks do them things do random stupid stuff like bite floats and fins for no reason at all and get very agressive when we have fish and get more agressive when poked in the nose with a spear.I can totally see why people would want 1 but I'm not guna buy 1 they are not needed with knoledge your safe. If I was ab diving there'd be no question it'd be as important as a mask or wetsuit as your mind is elswhere. Would love 1 to hang under the boat to keep them off my reds when line fishing though.