In my area, it is common place that if something is placed next to the road (unless obviously meant to be there) it is up for grabs.
Bagged leaves, old bales of grass, scrap metal, ect ect.
I've snatched a few bags of leaves from known pollinator-friendly households without hassle. There was one time someone asked me what I was doing and after I explained they were happily amused. I'm willing to take on some quick social awkwardness for improved soil.
