Ok well I thought I'd just toss in a thought or two, but ignore if you feel like it!
First things first, theft should never happen. It's a crime, and the people that did this are probably scum, that sell to armed robbers/hoodlum wannabes/etc. So I want to say that I understand that part.
Secondly, Doesn't matter now (speculations/ideas), it all means nothing now. The guns are gone, and I REALLY hope they are recovered (maybe someone stored them all in one spot- that would be lucky).
I also understand that the manner in which they stole the guns, well... there was little that could be done there. Their security was up to standards I assume, but the thieves just went a little higher up (as mentioned before, few things are truly impenetrable in a situation like this).
The one thing that I DO think I agree with, that was a bit controversial ... the guns display cases/etc, should be empty. it is VERY tempting to have all those guns in cases, ready for the smash and grab tactic, like a jewelry store. I like what was said about not having items out in the open (so to speak), but rather in a vault. I know its a tedious extra step, but it's a good one. Just because the firearms were stored legally does not mean it was a good method of storing them, right? (sort of like "it is legal for you to leave a chainsaw on your deck unattended, but not too bright if you have kids around" logic - that's a very bad example, but you get the point hopefully)
One thought; To know that guns are laying around in cases like that requires knowledge of the inside of the store. Chances are that one of the thieves/the thieves had visited the store beforehand to get a good idea of the layout/what is available.