Maybe enable the buddy sistem, just like on Starcraft 2.
If your buddy has the full game, you can join him on team games and play with vanila armies, like soviets and ostheer.
If he likes the game he will purchase it, getting access to the campaign and all ToWs.
If you get caught hacking or exploiting, your buddy with the full game would be responsible for you, so it avoids people creating fake accounts to test hack tools.
