ORIGINAL: -pkh-
The only time I've ever heard of LiPo's being a problem is after overcharging or over discharging the packs. I keep an eye on the packs while charging, use a Wattmeter and appropriate ESC voltage cutoff to ensure my setup doesn't over discharge. For storage, I don't worry about them.
Same here, I have never heard of a Lipo catching fire just sitting around on a shelf. If they were that unstable they would be outlawed and No store in the world would stock them or sell them.
I would bet that 99.9% of problems only occur because of improper Charging/discharge or a major crash/mishandling resulting in damage to the battery.