Certain governments seek to maximize terror and murders. One strategy is to prohibit concealed carry licensees from carrying on public transit systems. Angelo v. District of Columbia challenged this ban. The district court denied that these licensees had standing to challenge the district's law. The D.C. Court of Appeals reversed that decision:
Otherwise, because the pistol owners have alleged a pocketbook injury that is caused by their compliance with an allegedly unconstitutional criminal statute, we reverse and remand the case for additional proceedings.
Most of this decision is about decisions concerning whether the economic injuries suffered by the ban qualify them to sue. At district court, the plaintiffs also need to raise a Second Amendment challenge. In the Framing Era "sensitive places" did not include either public transit (there was none) or private transit. In various cases in which I have worked, their side has attempted to argue that post-Civil War railroads prohibited private possession of firearms. Their evidence has been either weak or non-existent. Railroads often required long guns to be checked. (People were going west to hunt.)