I use one of thsoe Havaheart traps to capture brass; it doesn't harm them.
To start with, if you paid for your ammo--even in those ranges that require you to buy & use their ammo--it legally belongs to you--not the range. No range has the right to say you can't collect your brass.
I try to keep my brass swept up to prevent people from stepping on it (a real issue with me). Most shooters do not reload nor do they care what happens to their brass. I ask if I can have theirs and offer to clean it up for them. That keeps me well supplied with brass. Otherwise, it's all a donation to the range scrap buckets. It might offend the range if someone gives me their empties, but again--it doesn't belong to the range until it's in their scrap buckets.