It is an interesting thing though. Why did the design lead too people leaving the cups behind? I get the hostile part as they do not want to clean up other peoples trash. It is something I think about a lot on the way to work. I see gum on the ground. Not like one or two here and there but hundreds of little blobs on the sidewalk. What is causing people in these particular spots to leave their gum behind and then putting the chore of cleaning it up on someone else. I even see it when there is a trash can nearby many times. What is causing the issue? So yeah so sometimes there is no 'clear fix' but making it seriously inconvenient to do something is an option for those who have to pay to clean it up. So we all suffer because of that.