All you electrical engineer know-it- all techhies bear with me on this post , this is just a common mans explaination basis practical experience and a little study.

Yep,
the problem was not with the recievers, the problem is using the wrong batteries for the application. This is true with any radio system. I would say that if you are performing aerobatics on a plane with several high output servos (100+ ounce rated output) then you might need to use a 6V setup and high capacity batteries especially if you are not very aware of what to look for and when you are at "no go" voltage. The problem is that if the voltage gets too low you hit the reboot voltage of the receiver. This can happen on 72mhz or 2.4ghz. On most planes that relative beginners are using for aerobatics if you use a 2000mah 5 cell NiMH battery pack you should be fine as long as you keep it charged. The risk is letting the battery voltage drop too far on a 4.8V (or any battery) and hitting the shutoff voltage.