I recall trying to get a paper or plastic bag from the kiosk vendors just outside Kanazawa station many years ago. I did my best to cadge one, but got a firm response: "No purchase, no bag."
I guess it's fair enough. They have to run a business. Their supplies of bags and water cost them money.
But there comes a time when such parsimony is counterproductive... I like to think that, after closing up shop, one of those merchants trod in the dog crap that I had been wanting to clear up with his precious bag.