The first most common crash scenario for a motorcyclist?
Overcooking a turn, going for the brakes, standing up the bike, and going off-line beyond the outside of the road surface, or into a previously occupied segment of the on-coming lane.
The second most common crash scenario for a motorcyclist?
Group ride.
If you always treat group rides as if you're surrounded by cagers (who do everything imaginable at random), you'll be fine. This is especially true if your group are strangers to you. Do what you would do if the cage behind you is on your ***. Do what you would do if the cage in front of you is being operated in an unsafe manner. In general, do what you'd always do on your motorcycle, but try to maintain the extra level of awareness that a group ride demands. ...and, for the love of God, cancel your turn signal after a turn.
In my experience, the riders in the groups at WFO and NAFO seemed to be a bit above average in terms of observable proficient motorcycling behavior compared to other groups I've ridden with. But as others have said, your ride is your responsibility and yours, completely, to control. There's no pressure to join a group ride, or stay in one if you're uncomfortable, for that matter. Just make sure, if you're going to bail, that you make it known, preferably to the ride lead or the sweep, and preferably at a stop, so that no one goes looking for you.