Visas for Eurobabes

When Eurobabes need visas for travel to shoot abroad, how do they get visas? Do they apply for work visas? If so, what do they list as the work: taking six dicks up the ass? On the other hand, if they're using tourist visas, that would make the porn biz a huge violator of immigration laws, with plenty of proof on video. What's the story?
Does it vary by country? For example:
Russian girl working in the EU (Buda/Prague)
EU or Russian girl working in the USA
Does it vary by country? For example:
Russian girl working in the EU (Buda/Prague)
EU or Russian girl working in the USA