My range uses spent brass recycling as part of the club's fundraising activities. People are definitely encouraged to police their own brass either for reloading or for putting into the drums and it is also ok for people to scavenge from the drums for reloading, but taking from the drums for scrap recycling kinda crosses that theft line a little.
Every range is going to be different. Even the ranges that do recycle their own spent brass probably wouldn't have too much issue with someone picking up off the lawn for whatever reason, but taking from the drums for cash might be a different issue.