I've had plenty of times where I get home and empty my pockets of the trash I accumulated with no can nearby.
And if I try to put something in a can and it falls out, I'm taking it with me because I didn't succeed in throwing it away.
Shrugging ans saying "well I tried" as you walk away isn't even trying.
I once dropped a water bottle out of my backpack, and couldn't find it when I retraced my hike, but I did start noticing tons of trash everywhere.
So I started keeping a trash bag in my backpack, and filling a small bag every time I hike.
I may not have found my bottle, but I'll make sure I clean up more than I left every time I'm out.