Seems to me that if people are aware that you are doing it (for safety reasons), there is nothing wrong with it. Having said that, fixie riders tend not to do it, either because they do not know how to, or because one rarely rides really long distances on fixed. I noticed that at the Brighton ride, where oftentimes people in front of me were twichy, changing direction fairly often), or where I tried to pull people who were obviously tired, and they would consistently back off away from my back wheel, losing the benefit of my being up front.
If the person in front holds their line and speed steady, it should not make a difference if someone is slipstreaming, since the person behind is not sucking up energy. Now, if sonmeone never returns the favor, that person is an asshole.
Seems to me that if people are aware that you are doing it (for safety reasons), there is nothing wrong with it. Having said that, fixie riders tend not to do it, either because they do not know how to, or because one rarely rides really long distances on fixed. I noticed that at the Brighton ride, where oftentimes people in front of me were twichy, changing direction fairly often), or where I tried to pull people who were obviously tired, and they would consistently back off away from my back wheel, losing the benefit of my being up front.
If the person in front holds their line and speed steady, it should not make a difference if someone is slipstreaming, since the person behind is not sucking up energy. Now, if sonmeone never returns the favor, that person is an asshole.