Drafting vs following too close is a tough call ... less than a bike length for long periods of time is definatly drafting.

I don't like being drafted by strangers, especially on my route (bike / pedestrian paths). There are too many walkers with ipods, 1.5 lane wide jogger packs, and homeless people lurching out of the bushes. I was drafted for a mile last winter by a stranger ... when the paths had patches of ice. I tried to drop him, slow down, everything but ask him to stop drafting. My final response was not good - and not one I would repeat.

Funny thing is, I almost had the same thing this morning. I was cruising along about to pass a pedestrian when a rider came around the corner in the opposite way, opposite lane. Unsafe to pass, so I slammed on the brakes. Guy behind me barely made it too. guess he gave me enough room or saw what was unfolding.