I've been out to BB 4x by myself, and every time I've seen other bikers and felt totally safe. My perspective is that the most important thing is to know your limits and when to back off. Today I started South Abyss and bailed out after two drops. It was still damp, and I know I'm not in shape yet.
I haven't come across any trail features that took me by surprise, so I didn't feel at risk there. The hike out would be difficult if you, say, had a broken ankle. What do people do when things like this happen?
BTW thank you to the young man that asked me today if I was lost. I was at Marker 5 catching my breath. I've had a great time so far, and felt totally safe, but then again I'm not burning up the trails. I've watched plenty of youtube vids, and I can't believe the speed some of you guys hit these trails. If you're going to ride like that, yes, go with a group.
I haven't had any wildlife issues -- I think common sense would prevail IE don't try to bunny hop a snake.