wasn't there a LiPO that went nuclear while stored in a Phantom in Aus about three + months ago - thought it was for sale on eBay...
Then there was an Inspire that lit up on a plane as the battery was left "on" while in the overhead
http://diydrones.com/profiles/blogs/dji-inspire-1-catches-fire-on-passanger-plane
My thoughts re: safety - store removed from craft. Make sure they are OFF! To that point I store my batteries in a First Alert fire proof file box that I picked up from Wallymart for ~$20... cheap insurance, rated to 1500 Fahrenheit for 1 hr. I know of others that use the old Ammo boxes from surplus stores.