I go by the following theory. My LHS has dozens of LiPo batteries sitting either on hooks, in a display case, or on a shelf. There are tens of thousands of the things (if not more) sitting in warehouses right now waiting to get shipped, along with those that are in transit to someone at this very moment. If they were that unstable we would be hearing about fires all the time and no hobby shop owner or distributor that sells them could afford the insurance

If the thing is damaged and I'm trying to figure out what to do with it it's different, but normally I do what they do at the hobby shop and put them on a shelf for storage.

The only time I have ever heard of one going off is if it was damaged in a crash or if someone was doing a demo and blowing one up on purpose.