My friend has recently purchased a new bike. The guy who sold it to him was clearly giving up the sport, so he gave to said friend his helmet as well (MET parachute for MTB).
As my friend already had a functioning helmet, he is now trying to sell the second one (within our rough group of people with whom we ride primarily). Now I personally believe it is just morally wrong to do this as he cannot know what the helmet has lived through, although it appears to be free of dents and has few scratches.
So am I being silly or is it just wrong to sell a second hand bicycle helmet?
Note: He sells the helmet he was given with the bike.