The City of San Francisco, upset at the increasing number of entertainers performing on public streets and obtaining funds from passers-by who throw money into a hat, passes an ordinance requiring all...

The City of San Francisco, upset at the increasing number of entertainers performing on public streets and obtaining funds from passers-by who throw money into a hat, passes an ordinance requiring all musicians who perform in public, whether for consideration or otherwise, shall obtain a license from the city each year and pay a license fee of $200.00. The band U-2 performs a concert at an outdoor venue in San Francisco. After the concert, the promoter refuses to pay the band because they did not have a license. If U-2 sues the promoter, will U-2 prevail or will the promoter prevail? Why? Please explain in detail.