I think I may be the kind of person we're talking about here. I wouldn't ever let a new prospect client talk to previous clients. They'd all immediately compare

I think I may be the kind of person we're talking about here. I wouldn't ever let a new prospect client talk to previous clients. They'd all immediately compare rates and try to low ball me. Conversely, I'd never take on a client "cold". Too many a-holes, crazy people and fraudsters out there. I only work for people I have a long history with, or on occasion the next transitive hop out on the network from those people. I would suggest that the counterparty do the same: reach out into their network and find someone where they can get a strong recommendation based on years of collaboration. If you can't achieve that, don't proceed with the project.