The fact that this is so many words makes me worry the author underappreciated the main lesson: risk exposure.

When you go out of pocket - you are out of pocket and the risk is all yours. If that one thing was different then all the remaining risk is on the client - they don't want to do version contr - ok cool you still get paid.

Usually when you have to pay in to get paid out (outside of a direct investment scenario) it's a scam. The people who fall for the Nigeria Prince thing are operating the same way.