As cyclist we should try to watch out for each other. Out of the three accidents that I have had this year, two of them involved other cyclists.
The one other accident that I had was a car backing out of a parking stall in a parking lot not looking behind him before he started to pull out. I wasn't able to stop in time and got hit, luckily for me he was just backing up and the speed was relatively slow. I only had a few minor bruises. This was back in August, since it was pretty minor with no damages to my bike I just rode off. Plus I kind of knew the guy.
Then about a month ago, I was stopped at a red light at the bottom of a hill. Suddenly I get hit from the back, at first I thought it was a car that hadn't stopped in time, I turn around and it was a guy on a mountain bike. He was looking down at his iPod. Luckily for me he hit me and my bike on the left, nothing was damaged. I could tell he was pretty embarrassed about the whole thing. The thing was, what if I wasn't there waiting for the light to change and he just sailed on into the intersection? Since nothing was damaged and hurt except for that guy's ego, I just rode off once the light turn green.
Finally a couple of days ago, I got ran into from the rear by another guy on a bicycle. We were going up a moderate hill (Ontario street, from 1st to 10th in Vancouver, BC). I think he was drafting me, the thing was at an intersection there was a four way stop. I slowed down and since there were cars in and at the intersection already I stopped. That was when I got bumped. I see plenty of cyclist that don't stop for redlights and stop signs and whilst I don't approve, it is not my skin on the line. Myself, I always stop, the thing to keep into consideration here is don't expect others to ride how you would ride.
Look out for each other out there, we have enough to watch out for already. The motor vehicles, j walkers and car doors. Lets not start taking each other out as well.
I also cringe every time I see people riding with over lapping front and rear wheels. This happens mostly when a group of rider has been bunched up by a red light and when the light turns they all just take off without being aware of where the other riders are in relation to them.
Be careful out there, bruises heal and skin grows back but there are some injuries that the body just cannot recover from.