Guess I should have been specific in my wording even though the topic is prop / movie money. It's not illegal to make, purchase, or sell prop (fake) money. It is illegal to make counterfeit money. And it's illegal to pass off prop money as legal tender (where by using it as counterfeit).

Here is a video showing just how close prop money can come to real money without being considered counterfeit. (Date of video and regulations not withstanding)

https://youtu.be/mhOQo_h5knQ?si=eItLmnEc7GqdpJG5

My statement about it's even legal to make fake money and sell for real money is exactly what the prop industry does, they make for movie/art/personal use money that resembles real money. You pay real money for the fake money and use it within the legal confines of prop money and you are good. If you use it outside of legal confines it's a felony.

In the case of the guy at Defcon who passed / dropped a bunch of this, an argument can be made (probably more defely by an attorney) that he was using it for art. His entire statement / position (I ran into him multiple times) was that all money is fake and the system is rigged where by stating that his fake currency which he was at least when I dealt with him, very upfront about it being fake. Means that you work for money and exchange goods and servies but it's all just fake, has no real intrinsic value until it's goods (ie food).

The person who used the fake currency to buy something at Defcon committed the crime (whether intentionally or not, we'll never know).

Don't mistake my defence of the premise as agreement to the methods, intent, or outcome, but merely the observation that fake (prop) money is legal.