Maybe. I'm actually on the other side of this as a freelancer, so might not have the best info. But one thing I've noticed is that one of main the ways I get gigs is by assuring people that the whole thing is going to work. In other words, there's a lot of inherent and perceived risk in outsourcing and if I can start a conversation, I can allay some of their fears. So it seems to me that with an upfront fee, you're tacking on this perceived extra risk or hurdle before they get to talk to anyone. I don't know what the psychology of money-back guarantees is. They don't have much affect on me, for some reason.