>>Why would you pick people who are not paying customers to be moderators???
Shelly gave you a great answer, but I'll answer as well.
I've seen no difference in the 'ability' of a user to Mod based on free/premium. It certainly helps if they have the premium features, but it isn't a requirement. A good Mod is a good Mod, regardless of membership level.
Further, if we were completely dependent on paying members only to Mod, this site wouldn't be where it is today..and even more chaotic.