They need to ask themselves first of all what it is that they want with this site. Generally if you know where you're going, you also know wich road to take. Personally I'm happy allready with free file hosting, wich is also a form of payment but I guess some might disagree with that.
This is internet and it's very young. I know, people think it's been around forever but I also know there are boys&girls out here who have seen it born. Internet, as it is today, is as leak as a sieve. Esspecially with copyright issue's and I've had this discussion before with people. You can implement all you want but the only real enforcement you have to your disposal is to throw/ban them from your site in wich they will create a whole new identity and rejoin. The same goes for security. People need to be a little bit more realistic, this is cyberspace, a two-dimensional world in wich anybody can be anybody.
A firm and strict policy wouldn't be so wrong. Internet is a bit like the wild wild west of the 21th century and all the diffrent laws can not be enforced for the simple reason that you don't really know who is behind the keyboard. You assume you know. On my own Forum I check personally who I "throw" out and believe me, that's not be cruel. That's protecting myself and the ones who really want to be there. It's alot of work, that's why it's not a big Forum...
Jake, this is your baby, this your site. Not ours. It's nice that you think of it as a communtiy and trust me, I do want to believe that. But it the back of my head I will stay on guard what I put down onto the web. That's why my social security number is a huge no-no because then I'm open to identity-theft since everything in my country is connected with that number. Over here if you have someone's social security number, you have their entire identity. But even a communtiy has a leader and sometimes they have to be strict and you are fully in your right to operate this site the way you see fit. That is with or without revenue.
If it's with revenue, pay per download would be a good idea. Maybe you need to make the site a little smaller, a little less in what you want to offer. Do you want to focus only on 3D or do you want to include 2D aswell? Art, is that really what you want? I'm just asking some questions here, not suggesting that you throw everything away. It's like I said in the beginning. What exactly do you want this site to be? If you would have a shop....what kind of a shop would you have? Something chique and fancy specialized in one thing or more like a supermarket? Diffrent goals ask for diffrent approaches. If you want to specialize in only 3D content it's going to narrow it down alot and the smaller something is the easier it is to maintain control and oversight. If you want it all then you have to accept the fact that the masses will come in and they can't be controled that easily.
I also read "login to download" and I agree with that one. It's not fullproof but it's better then nothing. You also might want to get in some real specialists when it comes to security.
Greetz from Pommerlis.