The seriousness of consequences is very high, but the chance of getting them is reasonable if you're well trained.

Consider that: most motorcyclists are there to have fun, so might have high risk behaviours, most motorcyclists are extraordinarily poorly trained, and it's a very high skill cap vehicle that requires ample training even for braking and evasive actions.

Also consider that it's a very small vehicle and those evasive actions have a high likelihood of squeezing through and avoiding almost any crash, and that the rider is often not even part of the crash they just slide to a stop.