I've lived and busked in two of the main UK busking Meccas, (both councils encouraging buskers) in the UK, namely York and Bath. Neither levied a licence, but I can see how one might be to the benefit of buskers and public alike, arbitrating as it might, against those whose art is, er, less than a learned discipline.

Also the universal etiquette in my experience has been to move on after an hour if another busker asks you when you might finish. Sorry, but those who claim that any pitch they happen get to first is their sovereign right to remain at till cockshut, are not being equitable and are militating against any notional code of busking ethics. Which is bad for everyone.

I recall in one of the aforementioned places, this fellow used to turn up on perhaps the best pitch of an historic street, and literally camp there the livelong day complete with dogs, rugs and what have you. He also put up a stall display with cassettes of his amplified, autoharp instrumentals. Discrete as his music was, his 'early bird' ethos would likely have disadvantaged a public for whom even a late-rising demi-virtuoso of whatever instrument would have been nonetheless a more nutritious listening experience.