They've got that one covered:
"S 400.10 Report of theft or loss of a firearm, rifle or shotgun.
1. (a) Any owner or other person lawfully in possession of:
(I) a firearm, rifle or, shotgun who suffers the loss or theft of said weapon;
(II) AMMUNITION AS WELL AS A FIREARM, RIFLE OR SHOTGUN WHO SUFFERS THE LOSS OR THEFT OF SUCH AMMUNITION AS WELL AS A FIREARM, RIFLE OR SHOTGUN; OR
(III) AMMUNITION AND IS A DEALER IN FIREARMS OR SELLER OF AMMUNITION WHO SUFFERS THE LOSS OR THEFT OF SUCH AMMUNITION shall within twenty four hours of the discovery of the loss or theft report the facts and circumstances of the loss or theft to a police department or sheriff's office."
Even drowning in the boating accident won't help, estates must inventory all firearms and report the inventory to the state.
Let's say the guns went missing somehow. I guess there would have to be a reason you're being asked about the whereabouts of your guns in the first place. So in effect you can drown your guns, report them as missing and hide them well until needed.
It's interesting that just those three states - Connecticut, Mass, and NY and beating their gums. Rahn Emanuel who did so well making the streets of Chi-Congo so safe he's traveling to DC to lend his knowledge.