It is the same for most visitors to Dubai. I learned a lot from those working girls.

I use it in my novels about how they swap and sell their passports, then buy another if they leave or they wait until the govt. has an amnesty, then get a residency. The Arab immigration people think all Africans look alike, so they come in on a 2 week tourist visa, sell the passport to a cartel and stay until thrown out, or want to go home. Then they buy another person's passport who has just arrived or one that has been tampered with.

The Nigerians are into everything, but the Chinese have inside help, and are more organised.