> ... subject to, e.g., ASCAP / Harry Fox performance rights organisation licencing ... to use only public-domain / freely-licenced works.

I know a couple people who dealt with ASCAP and BMI in the context of small businesses. The association reps sounded a lot like stereotypical mafia "enforcers", making "It'd be a shame if something happened to your business..." kinds of veiled threats even when told the venue had strict rules allowing only original or public domain performances. (Their people also kept coming back, over and over again, much like vampires.) This was nearly 20 years ago but I doubt their tactics are much different today.