WinterChild , Busking in Charlotte NC USA is not a problem at all.
You don't even need a license unless you have an amplifier.
The down side is .. you DO NEED and amplifier to be heard over the noise and there are not a lot of places to play .. AND i don't think the people are very generous.
Your looked down on as a bum ..
ALSO: the laws state that you must play on public property and not impede the movement of traffic or pedestrians.

You apply for license with the transportation office.
** which i thought was kind of odd .. **

I've yet to contact them about cost involved in amplified license.
Also there are restrictions based on the total WATTS of power and volume of the music in decibels .
The city is noisy with many construction sites .. i can't imagine what they would consider to be too loud ..
and again ... if your awesome .. nobody will really care as long as you have a permit.