It's all about the care and feeding of these batteries. They need to be treated and charged properly. A lot of good information has been posted here. Almost every instance of a fire that I have herd of has been during or after a charge cycle. There are tens of thousands of lipo, so sitting in cases and on the shelves in hobby shops across the world. I have never heard of a hobby shop burning down due to a lipo fire. This should tell us something. Never trust your charger unattended. (Most are made in China) Monitor current and voltage going In to the battery throughout the whole charge cycle. If they puff get rid of them, if the cells don't balance within a couple tenths of a volt to each other, get rid of them. Keep.them cool and dry and don't store them at full charge.
Vince T.