Linking the No-Fly list to exercise of a Constitutionally-protected right will make the No-Fly list subject to judicial review.
Right now, the list is "secret". There's no published criteria for inclusion. There's no procedure for being removed. Linking it to gun ownership will require that it be opened up for all to see, and will make it subject to challenge.
There is scant reason to assume precedent, logic, reason or decency mean anything to the legal class.
Excellent point.