Also if you have 2 aileron servos plugged into two channels of your receiver, and plug them into the wrong slots (right aileron into left slot, etc.) it would fly as if the channels were reversed. Of course you are supposed to do a preflight check, but I imagine we're all guilty of not doing a full preflight at least once in a while. It happened to a very experience pilot with a new plane at my club (last year? I wasn't there, but heard the story.) who was maidening a beauty new plane. He took off and the plane rolled a little to the left as it left the ground, so he gave it some right aileron, and it rolled left even more; he slammed right aileron not understanding what was happening (all happening so fast) and slammed the wingtip into the ground, cartwheeling the plane into a pile of splinters.