Almost all of the older and new cheapy chargers are just peak detectors and do not have software and hardware safety features. Even at a 1C, if the pack has a bad cell can still rupture at 1C if the charger is a stupid charger.
High powered iChargers, PowerLabs and other incorporate intensive software/hardware safety features. There are still a lot of fancy packaged RC car chargers that lack safety features.
A good lipo bag is also important as added measure. Saw this on YouTube but can't seem to find out who sells it.
http://www.youtube.com/watch?v=iX1MdkSU56M And the other question, who makes the best Lipo bag?
The Turnigy bunker is very effective and can be reused again whereas a bag is one-time-use.
http://www.youtube.com/watch?v=rusHrUSMmcw