I always throw my trash away. And if I'm with others who are about to walk away and leave theirs, I tell them to throw theirs away too.
I got a first hand experience dealing with other people's trash recently. I was invited to my grandson's football scrimmage game, and drove with the family. After the game was over, I thought we were going to hop in the car and leave. Nope! Their organization sponsored the game, so it was up to them to leave the high school stadium as they found it before the masses came for the game. That included trash duty.
So I round up my all my grand-littles (minus my one year old lol), and a couple of boys from the team. We collected all the trash from the bleachers, and threw it away. It was disgusting to see how much trash people left with no regard to how it was going to get disposed of. My grandkids were even appalled. A lesson came out of that experience for them, and I will always remind them of it when I see them walk away from their trash. (which I always have before then though) Needless to say, I was forced into the situation, and was a bit irritated.Ok, quite irritated.
Moral of the story ... people, pick up, and throw away YOUR damn trash!!!!!!