I love the last part "order could mean directive", like he is in the DaVinci code. A money order is a thing. They mean that thing. The secret code is that there is no secret code. Pay your bills.
The way that I'd explain some American Sovereign Citizens is that they are low information people who don't understand the legal process. They see people make statements, use big words and sometimes Latin, and argue what they see as small technicalities. It would be like a muggle watching Harry Potter cast a spell.
So they are trying to cast legal magic like Harry Potter.
You have to order them to do it first. Something as simple as "put the money in the bag or else" on a note handed to a bank teller should do the trick, I've seen that work in educational documentaries on the television. The "else" here is putting a lien on their corporate strawman but you don't want to tip your hand too early by spelling it out.