I am very sad to read this. As an international touring artist I know how hard it is to make a work permit for sigle performances and sometimes I also have to travel to countries without the work permit. For guest performances it is just a very bad situation for the artist. Of course its different if you work as a musician for a longer period, playing several times and for the same host. But touring artists with guest performances should be able to perform their art, it benefits everybody because art is unique and not a "job" and performing art is not a crime. I have been welcomed to perform across 87 countries so far and I am very happy that something like this has never happened to me yet... lets hope it stays that way. By the way, Europe does it right, artists can perform as guest performers without work permit across Europe - because art performances are not seen as "work"