How many of us have done this before?
I frequently find myself picking up others' discarded trash in order to dispose of it properly. Lazy assholes can't be bothered to do it themselves, so I'll do it for them, and silently direct invectives in their general (unknown) direction as I place the object in the correct receptacle.
Aside from picking up blatant asshole-deposited trash, how many of us have returned from a run carrying something more useful which we found lying on the road? I have come home with a wool U of M hat and a colorful tote bag.
The smorgasbord of clothing left behind at the start of major cool-weather races is a serious temptation, as are the innumerable hats, gloves, arm warmers and the like scattered on the road in the early miles of a race, but I do my best to refrain from picking up anything because I probably won't want to carry it for the next 24 miles.