I’ve an experience related to: The Straight Dope: Can you write a check on any old piece of paper?. Utah in the late 80s, I had a surplus of deposit slips so I started using them for checks. This worked fine for the local pay by mail mortgage and utilities. Then I sent one to a mail order seed company out of state. They somehow converted my check-on-a-deposit-slip into a bank draft, or some such, and it cost me $10 in fees to pay for a couple dollars worth of tomato seed.
Nowadays, you can’t even expect real checks to be accepted, if they aren’t imprinted with account number, name, address, and check number. If you want to start a new business, be prepared to pay cash until your custom checks come in.
“Eben Grumpy of Iowa was a little slow in paying John Sputter $30 he owed him. Sputter threatened to sue, so Grumpy painted a check on a door and dropped it on him from a third-story window next time he came over. A court ruled the door was legal payment.”
This “example,” is likely fake too. Eben Grumpy? “I’ve been grumpy.” The name’s a joke, and the situation is too, I imagine.
One early version of this legend - which Cecil mentions in passing - first appeared in the British humour magazine Punch back in the 1920s. The article was fiction, but was reported as fact when it reached the USA and gained still further credibility when adapted by BBC television in 1967. More details here: http://www.planetslade.com/archive/thecashcow.pdf