Even volunteers have power. The question is how much? Often workers (paid or unpaid) believe they are irreplaceable, and start acting that way. It behoves management to find out if that is true. It can also help the relationships a lot if the workers find out its not true.

We're all in relationships with others all the time. I can push my suppliers some, but not too hard. I complain about other suppliers, but in some cases have little power so walk softly.

Reddit moderators believe they have power over API pricing. I guess we'll see who is right.

The majority yes, but some of them are Reddit employees and are paid.