I think it is clear that the gov't can force you to make a false statement, including forcing you to leave your canary unmodified. At least within the limits of what threats of violence can achieve. I'm going to assume that is the case. That carries some pretty ugly realities with it about the nature of our gov't's recent conduct, and probable future conduct. Good luck to anyone who ever has an occasion to challenge the gov't in a situation like this and does so.