I have been on both sides of this situation. I have been passed and then paced the rider that passed me, usually staying back 10+ feet because I don't want to benefit off their draft as I am out there for a workout, not to draft. I am not pacing them to annoy them, usually it is simply the fact that we are going the same speed. Many times after they pass, they cannot maintain their speed, so then it leaves me in the situation of either passing them back or slowing down. I have also had riders pace or draft off me, which I really don't mind as long as they let me know they are back there so I can signal any hazards in the road. So, even if you stay 6 feet back, you might let them know you are there so they don't make any abrupt moves that could endanger both of you. Even though 6 feet might seem like plenty of room, some people might feel like you are drafting.