Maybe a deal could be struck with online servers doing automated checks to see if someone is using a duplicated copy? I recently bought Condor flight sim (glider sim), paid for it and downloaded it online (which was absolutely painless), installed and activated it once(activation code by way of email).
Now I could install it to another PC and it would work, but if I tried to go online with both copies running, the server would pick this up and render useless the aircraft of one of the users (makes glider sink a -4m/s which is cruel to a glider pilot
) and I think the same is for trying to use a LAN.
So that might also be an option for the online side of things, but alas it does nothing to stop offline players...
I was a bit sceptical about buying and downloading software, but I after trying it, I would welcome the chance to do it again. Broadband would also be a must though...
It never ends does it?