Actually there is a FEDERAL law that says it's ok to have an unloaded locked fire arm but Ma. Ill. and possibly some other states (Ca. ) ignore it
This is what is currently on the books so the case you mention may have forced the changes...It does not mention handguns that I can tell but I'm still trying to read the entire document.
Chapter 140: Section 129C. Application of Sec. 129B; ownership or possession of firearms or ammunition; transfers; report to executive director; exemptions; exhibiting license to carry, etc. on demand
Exemptions for non-residents;
(f) Possession of rifles and shotguns and ammunition therefore by nonresident hunters with valid nonresident hunting licenses during hunting season;
(g) Possession of rifles and shotguns and ammunition therefore by nonresidents while on a firing or shooting range;
(h) Possession of rifles and shotguns and ammunition therefore by nonresidents traveling in or through the commonwealth, providing that any rifles or shotguns are unloaded and enclosed in a case;
(i) Possession of rifles and shotguns by nonresidents while at a firearm showing or display organized by a regularly existing gun collectors’ club or association;
(u) Any nonresident who is eighteen years of age or older at the time of acquiring a rifle or shotgun from a licensed firearms dealer; provided, however, that such nonresident must hold a valid firearms license from his state of residence; provided, further, that the licensing requirements of such nonresident’s state of residence are as stringent as the requirements of the commonwealth for a firearm identification card, as determined by the colonel of the state police who shall, annually, publish a list of those states whose requirements comply with the provisions of this clause. ***
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Right now that list has NO states on it.