The penalty for selling drugs within 1,000 feet of a school or house of worship is
enhanced, and I would bet it's illegal for a civilian to carry a rifle into a
hospital, as this murderer did. An elsewhere-lawful activity, drinking alcohol, is prohibited in public, while driving, and even having an open container of alcohol in motor vehicles is prohibited. Why couldn't we make it a crime for
non-law enforcement to possess on his person a rifle on or near the
property of any place of mass congregation, including e.g. a hotel or arena?