I remember not long after i joined ecf reading a story on here where a guy had bought a mod, and the battery for it, then taken an extra battery with him to work or wherever he was off to. Unfortunately, he put the spare battery in his back pack loose - not in a plastic case or anything, just in the bag. It exploded, but as it was an AW IMR it wasnt anything like as bad as it could have been.
The difference between ecigs and laptops / mobile phones, etc is that none of us charge our phone / laptop batteries externally, we dont carry around spares for laptops / phones as its just not necessary. Ecigs require a little more safety awareness - When we charge our phone we tend to use the charger it came with (if you do use chargers that you bought cheap off a market stall then you are taking a risk) so we pretty much know its ok. With ecigs each kit / mod that we buy may or may not come with its own charger, even if its safe we may end up with a few that arent all compatible, but we also end up with mods where we have to charge our batteries seperately and may end up carrying spares around - thats where the problems start.
Considering how long ecigs have been going now and how popular they are, plus how stupid some people can be i think it's amazing that there havent been more accidents. Hopefully this is a sign that people are careful and that vendors are at least giving a mention to battery safety and making people aware of the potential dangers.