Actually, it's the intructors fault(s) for letting them act like that in the first place. Putting someone into a type training (randori or otherwise) that is too advanced for their level of skill and understanding, as well as not explaining parameters for behavior in the dojo.
I've had my shoulder seperated and dislocated (at the same time), forehead split open and taken an escrima stick to the temple. All from white belts. Yes they are dangerous but if you take things slow, make the rules clear, watch them close and lastly don't take them too far into something they are new at too quickly their level of threat is mild.
Biggest danger I've seen from white belts is that they will try things blackbelts do on purpose but do it because they have no idea they shouldn't do that. ;)
I find the dreaded WB spaz to be a complete pain if left with an intact illusion of strength. There is nothing worse than giving a new guy the benefit of the doubt in your first match with them, only to watch them hulk out on you when you going 50%. You end up under them and have to now work on getting a guy doing nothing but clinging onto your head like a rabid chimp off of you. The WB views this as a victory and continues to do this to others.
I find the most effective way to deal with them is to tap them out fast and dominate them from the the jump. No guard games from them, just mount, knee on belly or rear mount. This is especially important for lager, stronger people who will muscle everything and have the ability to hurt others with their retardation. After I rough them up a little they tend to calm down as the pecking order is established, and they can see that there is something of value to learn if they simmer. If they do not have this realization, then I continue to choke them time after time until they do. This also keeps them from being a jerk to newer people in the class, as they know what just happened to them and they are not invincible.
On the other hand I enjoy rolling with the WB spaztard as they are a prime example of what you find on teh streetz. It is great for keeping you sharp and reminding you that the world is not playing by the same rules you and your training partners have on your schools' mat. Its just a guy trying to win at all cost.
Here's my thread over the destructive power of the White Belt.
It took me 6 months of revalidation before I could train again and now more than two years later since my return, my right knee acts up.
Couldn't train anything for now the third week in a row, because my "lean, fit Muay Thai classes" are to demanding on the knee (too much thaipad drills). Will see how it is next week and then just the normal MT class (once a week) and the normal Savate class (also once a week) and no more "lean, fit MT classes" and no competition ever again in a kickboxing style.
Lucky the difference in the striking arts between the n00bs and the advanced people avoids some of the worst problems like the the ones the white belts causes in grappling. In my experience the only white belts that can give problem are the big agressive ones like ex rugby players or just weightlifters.
Being sincere reading this stories about such stupid people causing so much damage really kills all my ideas to star grappling.