Are these people more interested in avoiding theft or fire and water damage? Is the average thief able to get into a gun safe?
Seems like John Mann had a basement vault and ran into a severe problem of flooding.
Also, if there was a house fire, some kind of flood protection that didn't rely on electricity of a basement vault might come in handy. All that fire fighting water is gonna go somewhere. A bilge pump hooked to the house electrical system won't work in a big fire or storm that knocks out power.
