His work was a scam from the start, he had the choice to stop or come clean at every point of the way.

He’s supposed to ensure the people represented exist. That responsibility shouldn’t go away because he paid some poor runners 10$ to write down the names.

Imagine a rule of law where that was a legitimate escape from consequences. I could sue your boss in your name for some made up bogus claim, and when you come out saying: “wtf, I never had any say in this!?” I could walk away clean with a “oh yea, that’s true and I knew that was the case from early on, but I paid this hobo 2$ to write down your name, and I had to carry on, just in case you’d want to actually bring the suit anyway”, while pocketing my cut of the case costs.

I'm basing this on your TL;DR, but not only did he know (no way to get rid of the fakes?), it also sounds a little bit like he gave them some winks along the lines of "whatever if they're not real, just bring me claimants".