This is a non-issue.

When I or anyone I see throws out perfectly good stuff, say after a garage sale or whatever we place it on the curb and possibly put a piece or masking tape on it that says free.

You don t go opening and digging in your neighbors trash can for salvage. This pisses people off because once some jerk has spread your trash all over your yard and street trying to get a piece of copper out of a something you threw away without the decent state of mind to put the trash they pulled out back into the trash can it makes you very hostile to these people.

Last I checked most functioning bikes would not fit in the trash can, objects sitting on the street or curb are not protected the same as the stuff actually in the trash can or recycle bin and can be taken if they are on public property. If you want something out of your neighbors trash and are to xenophobic to knock on their door and ask them, then it's a personal issue, the laws that are in place to protect trash are their because of scrap yards making messes and not cleaning up after themselves and the nature of the sensitive information in people's trash and the biohazards that people trash presents.

If you pulling stuff out of an apartment complex dumpster and some patrol cops sees you they are going to bust you and there is plenty of precedent as to why that happens. If you are calm and like hey officer I was after this bike right here, then chances are they are going to let you go if you don't act like a jerk