BC's rules are mainly dictated by insurance and liability, so any events organised through them need helmets.
No big deal. Your choice. Ride or don't. I personally wouldn't be without one - road rash on the thin bit of skin on your scalp can't be nice. In my latest accident, I actually didn't hit my head, but the previous two required new helmets, and saved me from concussion. It was nice to be able to rest my head on the back of the helmet whilst I was pinned to the tarmac by a nurse and paramedics, rather than my head resting on the cold, wet tarmac. Very glad for a winter soft shell as that saved me from getting very cold. I was cold enough that they struggled with an IV line !