Since you can't do a patent search (I presume) on secret patents, how could they even enforce the stupid things? :-/

As Wolfgang Pauli used to say "this isn't right, it's not even wrong!"

When you attempt to register your own patent, the patent office does a search, and if your patent matches something secret, they tell you it already exists and you can't have it. Generally the government forcibly buys your patent from you.