It happened in the US where after the man deceased, his wife couldn't claim the pension and his estate (inheritance). That is because their marriage wasn't legal. Luckily, he had underage kids, and the govt allowed them to be beneficiaries of the pension. However, because he didn't leave behind a will, inheritance tax hit them hard and whatever money that he left behind was taxed 50%.
I brought those points up because none of us know when we're going to die. Therefore, marriages must be documented and legalized through the courts. Fraudulently sponsoring someone put those benefits that family may need a critical times at risk.
Lastly, instead of filing sponsoring relatives, you can work your butt off and send them between $3000 - $5000 USD, and they can start a good business in Africa. It doesn't always need to come to the West to make a living.