I've seen a few videos and tales of multi-rotors and planes falling from the sky "flip of death" and such. They are all very old but I'm wondering if that sort of thing still happens.
Some of those type of failures were caused by "brownouts" on the flight controllers due to unregulated voltage supply from an ESC. With the new power modules supplying regulated voltage the controller failures have reduced a lot. Another reason was that the servos were powered from the FC board causing brownouts.