Actually no. Last time if i remember correctly, Al-Arqam use this method every friday. Just pay as u wish. If u pay more, its your derma. If u pay less, they derma to u. There is one muslim shop at my place did the same thing too last time. And evey friday, lots of people will derma there too, from banana to bread, cake, muffin. People will just take and pay as they wish.

But of course that one was last time lah, 90s to early 2000s. Nowadays people have less moral value, so u may be right in some sense.