What no hair & nail samples or home inspection? As a contractor could see them checking out your company credit (if it was a large dollar amount or to see if any legal issues with proprietary information involved or high security clearance type materials (govt contractors)
But on the personal side, would not care how good the single contract was, would say no thank you. Unless
They provided you the same information in kind. The last 3 years of their tax filing statements. All their executive board and directors SS, credit reports and backgrounds
Oh and UA's & psy evaluations of every person involved in the project.