Watch a few videos on sway accidents and you can often see what caused them, BUT NOT ALWAYS. Load balancing is extremely important - too heavy in the rear of the trailer - extremely bad, too high of a load in the front can be almost as bad.
I just got done researching a bunch of different sway and weight distribution hitches. Everyone has their own opinion on these topics. I was looking for something that eliminated the typical creaking and groaning that most hitches have as a result of the friction used to prevent sway. Most are bars that slide on a stationary bracket/friction point. I also wanted to eliminate the lubrication most bars required that people complained got all over the place when storing the bars. Last but not least, I did not like the bars that used a pipe to cinch up the bars by lifting up. I have problems with my shoulders. Sway was my biggest concern. I looked at ProprIde and Hensley - supposedly the absolute best and to me they were great with sway, but far too complex and a pain to hook and unhook. I also looked hard at the Reese Straight Line but did not like the noises it made and the need to unhook the bars for tight backing turns. I settled on the Blue Ox Sway Pro. The only thing I'm adding to it is a good 24" breaker bar and socket instead of the provided wrench. The key to the Blue Ox is to make sure you jack the tongue up almost as high as you can get it to relieve the amount of chain tension to install or remove the bars. People that follow the rule of relieving the tension find them very easy and safe to use. Set up is everything on any load distribution hitch. I read some bad reviews on almost every hitch. Husky had more most.
Not to scare you but I don't buy sway control isn't needed. I rented a 20' single axle trailer - had the tongue height right and there was NOTHING in the trailer or tanks - it swayed at 65 MPH.
Speed is the biggest killer - especially downhill. High winds, rain, snow and semis passing can also trigger or destabilize a typically stable rig.
