IIRC, the ASGCA had a number of model or template practice range conceptual drawings in the 90s.
I suppose customs are different in various parts of the golf world, but here it is totally customary and normal at public courses, even daily fee courses to pay for buckets at the range and use your own shag bag at short game green/bunkers and putting green.
I did this at Ravisloe a few years ago and was told to leave by an overzealous marshall, who told me I was only allowed to use their decidedly average at best range balls on the chipping facility. It was very frustrating. I showed up and hit two buckets of balls that I paid for, then grabbed my shag bag to use their chipping area (which is, or at least was, pretty nice). This was on a day where I was the only customer in sight. I wrote a letter to their head pro (no response) and refused to go back for a few years until reluctantly agreeing to join some GCAers. The really stupid thing about the situation was that if I'd bought a bucket of balls, I could have used the chipping area for hours, then picked them up and hit them at the range, and they would have been perfectly fine with that.
Generally, I think if you expect people to pay to use the putting green and short game areas for practice, you should tell them. Whether the price of admission is a round of golf, a bucket of balls, or just some user fee, let the customer know. Personally I feel obligated to spend some money if I'm using someone's facilities, so I'd probably at least hit a bucket of balls as well, but plenty of people probably don't feel the same way, and that's perfectly fine. The course should just be up front about it.