I get really annoyed if someone drafts off of me without asking. I am not a very experienced rider and it makes me a nervous wreck to have someone back there. On that same note, I would never draft off of a stranger because I'd feel like I was putting us both at risk.

There was recently a serious head-on colision on our local bike trail and three riders went to the hospital, all with broken bones and one with abdominal trauma. I'm not 100% sure of the exact circumstances, but evidently one rider swerved, causing the rider drafting behind her to crash into oncoming bike traffic. I have no idea if these people were drafting with or without permission from one another. But if it was anonymous-not-asking-first stranger-drafting, then I bet everyone was pretty angry.

I would much rather have a stranger ask me than to just have someone attach themself to my back wheel. Then I could tell them that they're taking their life into their own hands if they want to risk riding behind me.