I wonder how it would have played out if a Watertown resident, with an LTC issued by that department refused to comply?
Given that it's a notorious "red" community WRT to issuing licenses, there's a good chance that the CLEO (Ed Deveau), would have used his discretion to revoke or deny a LTC upon renewal.
See Godfrey v. Chief of Police of Wellesley
http://www.constitution.org/2ll/bardwell/godfrey_v_chief.txt
The only relief for Mass residents in a situation like that is to get out of the Mass court system and into the Federal system. I'm not a lawyer - but I think that would require challenging that the issuance at the discretion of the chief of police is itself unconstitutional.