vBulletin could care less about what he does with code that doesn't belong to them. They can revoke his license for anything they want to. Even if it's a reason like "You never sent a pizza to our corporate office last week." Because any good company hides in their TOS that they can revoke your access/license "for whatever they deem fit." Basically you're playing a game owned by them, and they also wrote the rules to and can change whenever. They could simply revoke the license because they want to. That aside, they don't care about what you do with software that isn't yours. That's between you and whatever company/studio wrote the piece. They'll come after your webhost/server ISP/whatever and send DMCA takedown requests until the faint from it. But vBulletin as a company, could care less. I would just run their nulled/whatever software and remove the copyright from them. If you have a legit vB board, and everything you are running that is made by vBulletin is legit, and you have the vBulletin main copyright in tact (per your license), you will be fine. The only thing you have to worry about is the third party software's developer(s).