I worked in a bank in the 70s. I remember the day's cheques being distributed among the cashiers for checking. Every signature had to be physically cancelled by the cashier initialling over it. You soon developed a rapid squiggle that bore no relation to your actual initials.Checking all those cheques is what kept bank staff busy, and is partly why there aren't bank branches and staff any more.
Incidentally, crossing cheques "account payee only" had no legal force until 1992.
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