I have a friend who participates in River Rides, Aspen Rides, these are rides where from what he tells me, hundreds of bikers get together and take a long ride in the spring, fall. It doesn’t sound like any kind of troublemaking at all and maybe even for a good cause.
As for Sturgis, all told, from 1994 to 2012, 141 persons have died, seems about all of them in bike accidents, coming and going and there. That comes out to around 7 or 8 a year. I know there are some wild hairpin turns there so if one is drunk, you can see what might happen.
---in the past there have been a few murders and once a three shot "suicide" but most fatalities are vehicular---