It's a real warrant, signed by a justice of the peace, and legally enforceable. They could have forced their way inside. They just have a policy not to do that if it comes to it because it's very bad publicity for TV licensing, so they withdrew. But by refusing to comply with the warrant, the person filming is actually committing obstruction of justice, which carries a much greater fine than just watching TV broadcast without a license. So he'll probably get a summons for that too.