Odd you mention that about machine processing

I think if an account has a requirement for two signatures (and maybe other specifics) they are handled manually. Our fire district has a two-signature requirement and the bank does catch checks that aren’t signed by two board members. (The check gets cashed when someone deposits it, but one of our board has to go to the bank and sign the check.)

Years ago (like 30)

I used to work for a mortgage company in the Los Angeles area. We made second mortgages. Firsts were going for about 13 – 14% and our seconds were 18 – 21% depending on the borrower’s credit rating.
We had one investor (that’s where we got the money to loan) who would save up all his monthly payment checks (borrowers paid us directly and we dispersed to the investors) until he had the appropriate amount for his next investment. My boss would call this guy and tell him he had a good loan for $xx,xxx dollars and this investor would bring in $xx,xxxx in payment checks (from us) to fund the next loan he was funding. Odd business that was. (I think a lot of investors, and my boss, really would rather foreclose because they’d be second in line to purchase the properties, but that’s another matter.) If the checks were over 6 months old, we’d do some fancy bookkeeping and reissue the funds to him so he could buy the loans. (I’m sure glad I wasn’t responsible for those checkbooks. I did the escrow books, general business books, and payroll. Others did the rental property books and the mortgage payments.)
I loved that job because I regularly got deposits in excess of $100,000 and then got to disperse the funds the next day. I loved balancing my books there.