Turtle n Peeps said,
"Notice it starts small and get bigger and BIGGER. Much like a wave in the ocean. Unlike a gust of wind which will just push you around a bit and then your trailer will snap back towing straight again."
I think that this is true in most situations; however, I will point out that the event that lead me to buy a Hensley was getting hit by a "rogue", very strong gust of side wind. It induced a real sway event that I was able to control with application of the trailer's brakes. My point is that the trailer did not "snap back" on it's own probably due the unusual severity of the gust.