With the required licenses a performer can worry less about getting caught in the act.
The only thing you know is that if you do not get the visa, you have 10 days to leave the country. It's a complete mind-fuck.
The Berne Convention requires uniform baseline protection, but generally this is based on the country of origin.
Copyright law can be confusing, especially with the abundance of misinformation circulated. In a perfect world, artists, art dealers, art lovers, and everyone else in the art community would live in harmony and there would never be any conflicts. Unfortunately disagreements do arise.