[qyichtym] Censorship of bulletproof

There is frequently censorship on how you can acquire, make, use, etc., weapons for hurting other people, e.g., guns and explosives.  However, is there equally censorship on ways to protect yourself from weapons being used against you?  For example, making materials and objects bullet-resistant.

Inspired by the Killdozer.  One can imagine law enforcement wanting to suppress information useful for someone else building something similar, especially information about how to make bullet-proof panels that would protect against the weapons the police would try to use to stop such a vehicle.

However, information for making things bulletproof does have legitimate uses, and suppressing information about how to stay safe seems sinister and possibly politically untenable.  Though it's unfortunate if freedom of speech is being granted politically only case by case.