I too have been asked many time to trade friend's money - never did. The extra burden is not worth the risk. If I'm good, I rather profit from my money, because the "trader manager fee" isn't worth it.
I accept as true with you because regardless of what the profit loss is if your own funds make more profit during a safer business, then the people closest to you'll not hesitate to be dishonest. Therefore, it's better to use your own funds albeit there's a risk we will do as we please and that we do not have to get on anyone's side.