I'm 6'3″, 200+ pounds. People draft behind me all the time. I usually ignore it and just run my own race. As far as my drafting off others, I do it if the situation presents itself. My rule of thumb is that if I draft for over a mile, I offer to take the lead.
the leader stopped in his tracks and stood there until the “stalker” got the idea.
I saw something similar to this in the Olympics during a cross country ski race (in 2002 I believe). The leader had slowed a number of times and the second place skier wouldn't pass him. Finally the leader stopped and made a gesture for the other guy to pass. The second place skier still didn't pass. The leader just took off and tried to open a gap. Sadly I don't remember which of them won the race.