Didn't check out the article, but this would be no surprise to me. I have been in the specialized flashlight mod world for a while now, and I know how dangerous li-ion batteries can be (specifically secondary rechargeable kinds, which is often found in most, if not all, ecig batteries).
I'm actually surprised this doesn't happen on a more frequent basis, especially given the crap e-cig chargers that are on the market these days which no doubt trickle charge li-ion batteries along with many other unsafe recharging practices. And if you are not familiar with li-ion technology, improper charging methods can cause them great stress and will cause explosions and leaks of great magnitude. Consider yourselves lucky you have not had any problems, because you are tempting fate with whatever ecig charger/battery you are using unless it is proven to be safe.
Li-ion secondary rechargeable batteries are nothing to squawk at, they are incredibly dangerous, borderline highly explosive bombs under the right circumstances. Which is why I prefer using my own 18650 batteries with my own trusted and reliable charger that strictly adheres to nearly every li-ion safe and proper charging protocol and offers true charge termination (one of the most important aspects to a safe li-ion charger).
If you want to know how dangerous these things can be, just go and do some searching on the CPF (candlepowerforums). If everybody here knew the true dangers of li-ion batteries (especially regarding improper charging methods) we wouldn't be so complacent about our ecig batteries as we are now.
And BTW for anybody wondering, Trustfire/Ultrafire type batteries are one of the WORST kinds of li-ion rechargeable batteries you can buy for a multitude of different reasons. Yes many vendors offer them as part of their setups, but it is foolish beyond belief to use such a battery. Stick to genuine Panasonic, Redilast or AW li-ion type batteries if you value your safety and quality of the battery.
Oh and a small tip for those charging ecig batteries, li-ion batteries don't like to be run down all the way and charged back up, they prefer small incremental and frequent charges well before they are dead. If you constantly run your ecig li-ion batteries dead and charge them back up, you are killing them at an exponential rate and will severely reduce their lifespan.