Entanglement seems to me to be location, or dive site, specific. For instance, I love deep wrecks, ocean and fresh water. Well anybody who dives wrecks knows that fish and other creatures love structure, but divers are not the only ones who know this, fisherman do as well. While diving the wreck of the Eagle in Key Largo FL this past July, my buddy and I were exiting the wreck after running a line. He had the reel so I lead the way out. After I exited I turned to make sure everything was ok and I saw my buddy tangled up pretty good. I had to cut him out, no big deal, but a nuissance. I would never dive without at least a knife on any dive, but when I dive wrecks I make sure I have two, or a pair of shears with me because fishing line is a common occurrance. I believe you have to be prepared for ever possible situation, if you think that entanglement is a rare occurence (which on 30ft reef dives it probably is) then you may not be mentally prepared for it if and when it does happen to you, because good chance some day you will get tangled in something. If you don't know what to expect or how to get out of the situation because you haven't prepared yourself mentally it may be an alarming event when most likely just attacking the problem slowing and calmly will get you out of the situation.