I have thought about this before, and I dont think it would be enough to give financial incentitives. It would clearly be a good way to show good will towards non-whites, but I would never assume it to be enough to let them leave. You certainly need some sort of pressure, too, like giving restrictions towards their social, cultural and religious life. This can be applied, however. We would ban halal and kosher meat, plus I very much doubt the non-whites would like to be around under a BNP government.