For an example of the first, consider that MA issued FOID cards that were valid for life, and then decided that they should expire after 5 years later. A gun owner who bought such a license might have thought it was, in fact, good for life and never did anything about it - but after it expired without his knowledge, the MA authorities have every legal right to kick down his door, seize his guns and jail him, because his "good for life" license has expired, he didn't know it, and possession of guns without a valid license is a crime.
For an example of the second, consider that Washington, DC, is a gun grabber's paradise, and the most violent place in America. Gun grabbers support all of the country becoming like Washington DC. Tell me, does that promote violence to you? Yet, the gun grabbing sites aren't blockable and the gun rights sites are.