Edited My post, fixed the WCA issue, I meant to say organizers.
As for organizers, you cannot simply hold them responsible for anything that could go wrong at a competition. Doing so would incur a great deal of insurance liability that would frankly reduce the number of competitions that happen. If someone doesn't feel safe dropping off their cube, nobody is making them do so. There is an extremely small risk that something like this could happen, usually in a public venue like where we held US Nationals, but that is a small risk one may have to take if they want to compete.
As for organizers, you can simply hold them responsible for anything that could go wrong at a competition, assuming they hold legality over the property that is being used. Although, we were on the topic of stolen cubes, your statement said anything, therefore I assume anything is in play. This organizer, under the law on Premises Liability, can be held responsible for far more than one thing that can and might go wrong at a competition, such as injury. Therefore, technically speaking if a risk has always been there, but has never been thought about, after a realization of the risk the number in competitions should not go down because we have simply been living with the risk the whole time. It's like saying, "After realizing someone
might drown in the ocean, we should close it down to public access, even though nothing has gone wrong before, and might never go wrong." Although I do somewhat agree with your statement. A cuber is taking the risk of getting hurt, and should understand that mistakes happen, but once again, it is the organizer's property, therefore, it is also their issue, and should be taken care of. With that being said, my opinion (and its fine if you have a different opinion) is that the cuber should know that an outside source might steal his puzzle, no one can control that human being's actions, but maybe it could have been prevented, if stronger precautions were taken by the organizers. All in all, I still think organizers should be held responsible, due to the fact that in the end, they are the force stopping anyone from causing issues with their competition. Whether or not they are donating their time is besides the point, if donating, you should donate that time to the best of your abilities, and realize that it was you signing up for that, so don't complain about having to do work that you signed up for. As for damaged puzzles, obviously, if a puzzle is damaged by an individual that does not hold ownership over that puzzle, they should try to do the right thing and at least give them money for repairs or a new puzzle, no matter if you are an organizer or a fellow cuber. As for the WCA, I wish the poll was stated better, by saying that the organizer should be responsible, as I find it silly to blame the WCA even though I typed that by mistake in my initial reply.