Ditto jtduncan's comments. My local indoor range lets me take what I want. They even go so far as to put me a couple of stalls away from the wall when not too busy, so I don't have to walk too far when chasing brass.
I've also had the same experience with a lot of neighbor shooters. Many of them show up with a brand new box of American Eagle or the like, and ignore the brass on the ground around them. I ask nicely and almost all tell me to just take what I want. I even have a couple of folks so well-trained, that they sweep their brass into a pile for me!
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Regards - AZFred