I doubt that was the case here. If you look closely the airplane actually snap/stalled twice. Once that took it into the spiral from horizontal flight and again just before impact. Just a poorly set up airplane that was flown too slow. The pilot was also holding a bunch of up elevator the entire time which just kept the airplane in a deep stall and caused the second snap.

Radio interference is something many guys should understand a bit better. I have seen installs that sent a chill down my spine. One case even had an antenna taped to an ESC. Interference and brown outs are not the same thing. A brown out is caused by a dip in voltage going into the receiver. More common with Spektrum as their critical voltage on the RX is about 4.5V. I strongly suggest running 6V batteries on any brand of 2.4GHZ systems. You should also always have enough capacity so that under high loads the voltage will not dip more the a couple tenths of a Volt. Unless you carry a Spectrum Analizer with you to the flying feild it is almost impossible to know what RF is in the area. Common sense would dictate that the more Urban your environment the higher your noise floor will be. Range checks are very useful. I always range check prior to a maiden flight, after replacing any electrical component in the airplane and when flying at a new site even if the airplane has been glitch free for hundreds of flights at the home field.