It is unlikely Tramadol would be thought by anyone to provide an edge. If the dog is in serious pain then that should be obvious to musher and trail vets and the dog pulled or medication allowed.If the idea is to force the dog to suffer PETA needs to be listened to. If the dog was given a therapeutic dose to treat lesser pain, this could make them also a little less eager. It certainly would not likely affect the outcome unless racers were seconds apart. So whoever did it must have either not intended to affect the outcome - perhaps providing a pain killer because the dog appeared to need one or as Seavey suggests to make him look bad - or the race was sufficiently close that it could have made a difference on the trail. How far apart were the Mushers towards the end? If any were within a minute or so they are the ones I would suspect. Either way the Iditarod ought to allow prescription drugs like Tramadol if a vet certifies need.