Trivia: The topic of xenophobia runs strongly throughout the film. This is a very real issue for South Africa as evidenced by the xenophobic violence in early 2008 where approx. 30 foreigners living in South Africa were murdered and hundreds left injured and/or destitute. In fact there are still displaced foreigners living in homeless shelters, churches, etc today.
Trivia: There have been protests against the alleged stereotyping of Nigerians in the movie. Two of the more sensitive issues are the Nigerian prostitutes soliciting 'prawn' customers; and the character name Obesandjo (which is closely linked to the former Nigerian President's name Olusegun Obasanjo).
Trivia: The 'prawn' design is based on an actual giant cricket species, the mole cricket, found in suburbs of Johannesburg. Commonly known as 'Parktown Prawns', they can grow up to 20cm (8in) in length.
Trivia: The alien languages and sounds were created by rubbing pumpkins together.
Answer: Yes. They weren't intending to visit Earth at all, but their ship became crippled somehow and they were all slowly dying. They made their way to Earth looking for help.
Phixius