>There's a youtube guy who goes around and landscapes people's yards for free. He does good work; it's a valuable service. But if he later returned to the house and demanded payment he wouldn't have a leg to stand on.

What you are describing doesn't sound free though. It sounds like in consideration for media and film rights - the compensation - the property owners get a service. It's like Extreme Home Makeover was done for 'free' for homeowners but was not remotely free in that was a broadcast cable show that people assigned certain rights to in consideration for 'free' work.

>That would be the same leg that the Reddit mods are missing.

There isn't exactly a bright line as to when someone should be considered a paid employee or not, but just with your own example, if that 'YouTube guy' was filming and profiting off the videos he made without releases from the homeowners he himself could be sued where it would be that he could owe the property owners, which is not a remotely applicable situation to Reddit moderators. If film, TV, commercials, etc are done on someone's property that's a whole different thing from employment law.