Apparently not everyone lives in a town where somebody cuts in front of you every 100 yards. We can only wonder what that must be like.

In response to the original topic, I gotta say I've never really thought of this as hazardous in the least. But if you're not comfortable, then either practice somewhere safe or don't do it.

People on the internet who have never seen each other ride are ill-equiped to make broad judgements on the safety of this kind of thing.