Exactly. When are you going to use a weapon? Unless you're a bike polo devotee it's pretty hard to handle something while you're on the bike and moving. Stopped, you're pretty much toast and you've thrown away all your advantages. It's just like the tactical driving courses they teach--keep moving. The extreme lighting mentioned above can help with the "jumped from behind a parked car" bit. You should be totally focused on the parked cars anywhere 'cause that's where the door prizes come from. It's gonna be tough to take a helmet light off an unwilling victim, and as long as it's still on it's gonna be tough to approach and see said victim.