Same as it ever was

Commerce through the ages suffered because credit markets were sporadic, unregulated and didn't extend much across borders between sovereign nations. However, beginning in the late 17th C the Quakers, with limited access to education and the traditional trades, found that trust could be very profitable. Therefore, in the age before every transaction was bound by a legal contract, the invented the handshake deal where both parties followed through. Thus "Quaker" become synonomous with honesty and quality and some manufacturers capitalized on this reputation, such as with Quaker Oats.

Unfortunately, recent events have found that some handshakes aren't worth the flesh that's being warmed.