When Ray Kroc attempts to buy McDonald's from Dick and Mac, one of the brothers' demands is "1% if the company's profits in perpetuity". However, when negotiating, Ray Kroc refuses to put this demand in writing, in the form of a contract, and instead offers a handshake deal.
I wonder why the brothers, and most importantly their lawyer, did not object to this. Mac seemed to be reluctant while shaking Ray's hand, but no one from their party said anything.
All throughout the film we see how Ray slowly pushes the brothers out of their own company. In a scene before that, Ray even makes clear in a call to Dick, saying that he is ruthless in competition. Surely they would have known by that point that Ray wasn't trustworthy.
So why did they not refuse a non-contractual deal?