This same scenario happend to me yesterday ...in reverse...sort of. I was inbound finishing my ride when I heard voices behind me. Two guys were close behind, riding double file (path etiquette says single file only) and having a conversation. They had been there awhile, then passed me. They didn't drop me...just got in front and kept about the same speed as me.
So...suddenly I found myself in a drafting position behind the two of them (still side x side and chatting away). So I drafted. I stayed a couple of bike-lengths behind them, but I was still drafting. I didn't ask them, but they knew I was there. What should I have done? We were all matched for speed; if I passed them again, they'd simply be drafting on me. I eventually dropped them going up a hill toward a bridge, but now I feel...hmm...was I rude?
~Sherry.