I would not advocate to litter - but there is a special case when I think you will agree that it is better to leave litter on the ground and keep walking.
Its a guy thing - having a slash at a urinal. I was finishing an enjoyable wee when a mountain of a man steped up next to me on the urinal - and started undoing his daks. I was finish - and at the wash station - and getting ready to dry my hands when the big guy opened his sluice gate. I lobbed the hand paper towel into the bin next to the urinal - and missed. The paper towel landed just to the side of the urinal - but close to gentleman that was a foot taller than me relieving himself.
To prosecute the recovery of the paper towel - and bin it - I would have to move to the side of the urinal, and drop to hip level - a position that would put me eye to (snake) eye with the mountain man, and about a foot from his crotch.
What would he think about me going around the side of the urinal and looking at his privates?
There was no dilemma - I walked out - quickly and left the litter.