A lot of it depends on how the shooting bays are configured, the gun and the shooters stance. Also, how can you maintain situation awareness when you are bent over or on the floor?
I'm mainly a revolver shooter and at a new to me range I have always asked if I could keep my brass, always been "no problem" just empty into your range bag.
At many ranges you would never get past check in with steel or aluminum cased ammo.
If you don't like the rules, go some where else.
Maybe true for some. Like I said, most of MY semis throw the brass to somewhere around 4 o'clock, so most of my brass ends up behind the firing line. The point being that "justification" holds no water for stopping me from collecting MOST of my brass since it is behind the firing line. I'm NOT advocating letting anyone go past the firing line to retrieve brass.
Personally I really don't worry much about maintaining "situational awareness" for the few seconds at a time that I stoop to pick up some brass at the indoor range - anymore than I do when at the outdoor range. It isn't as if someone is likely to come to a gun range to perpetrate a mass shooting - those nutjobs virtually always choose "gun free zones". A shooting range where people are armed and prepared to shoot back is about the last place you need to worry about being situationally aware of threats. Picking up my brass doesn't detract from safety either. I can pay attention to other's gun handling just fine and still pick up my spent cases.
I've been to more than a few ranges and never seen any that restrict use of aluminum or steel
cased ammo. What would be their rationale for that? That they can't make money stealing your brass? I have seen ones that won't allow steel or steel cored
projectiles but not cases. Almost all prohibit steel in the projectiles - to protect their backstop. Since you're obviously familiar with some ranges where their rules prohibit the use of steel or aluminum cases, can you share what justification they have given for that rule?
Regardless of why, if they insisted on confiscating my brass, and won't allow non-brass cased ammo then they wouldn't be getting my business anyway. I think I pretty clearly stated that earlier - that I indeed WOULD be going somewhere else.
If you like places that operate that way, then more power to ya'. I have no more objection to you giving them your money AND your brass than you do with my refusal to give them mine.