The "they'll turn on you unpredictably" argument...
This is a claim that is difficult for anyone to prove for any cat. It doesn't make any difference if it's an 8-pound domestic tabby, or a 500-pound tiger--all cats' play is predatory behavior: stalking, pouncing, biting, grabbing. Even domestic cats do it, and a play session can quickly turn into an unpleasant situation for the owner if they haven't taught the cat playing limits. It's not so much that the cat is "turning" on the owner--the cat may be a complete lap cat at other times, and sleep cuddled-up with the owner. But the play thing just gets out of hand.
So it's possible--even likely--that many "attacks" could easily be play moves that are misinterpreted by observers and people writing about the event afterwards--or it could start out as play, and then just gets way out of hand. Any videos or pictures you see of exotic cats playing by stalking their owners or trainers can easily be misrepresented as actions of an aggressive animal.
The other problem with this argument is that there are no statistics or numbers of any kind to back it up. Even if ban proponents could supply the number of times captive exotic cats "turned" on their owners, in order for that number to mean anything, we'd also have to know the total number of such exotic cats in existence, in order to estimate the percentage of cats that do turn on their owners (to know if it is, in fact, a problem). That might start to give an indication of the probability of that happening. But honest numbers simply do not exist--not of the number of times animals seem to "turn" on their owners, and not of the total number of exotic cats that are in living in captivity in the US.
If someone does quote numbers, those numbers need to be viewed with suspicion--if not totally disregarded. Any time someone quotes numbers, they need to be held accountable for the accuracy of those numbers. Others need to challenge the numbers and make people substantiate their claims with verifiable sources of their "statistics."
The only people who will even try to get numbers on such a thing will be someone trying to "prove" one (or the other) side of the issue--not exactly your unbiased scientific observer, and (very often) not even anyone knowledgeable in the proper analysis of statistics. A prime example of this is when ban proponents cite estimates of 10,000 to 15,000 tigers in captivity in the U.S. [1]. That's tigers alone--no other species are included in that "estimate" They cite no source for their "estimate," and they don't explain how they derived those numbers. They just briefly say it's an estimate, and then proceed with all their arguments using those numbers as if they were proven, verifiable facts--when they are not. This pulled-out-of-the-air claim of 10-15 thousand tigers has no factual basis, and is being used solely to try to make exotic cat "safety" look like a big issue that's important--when, in fact, it means almost nothing to the public at large.
References:
[1] http://www.api4animals.org/articles?p=188&more=1
--Greg Lyons
