I read through the thread a little bit. I would say the first pack you shouldnt have been charging at 1C and then knocked over. The 1C charging may not have been in spec with that pack, but since i dont know that C-rate it is, its hard to tell. I would say that failure is called for.
Now the 2nd one is odd. I would be interested to see/know more details about when that battery was purchased and how it was treated, etc. But it sounds like it really did just fail. A little scary.
That being said you should expect a 10% failure rate (dead cell/puffed cell) from HobbyKing. I have 42 cells (in various packs) that all arrived in great shape (20C 5Ah). The explosion seems super rare to me.
My 2 cents. Thanks for the interesting info Larry