Controlling Sway Stresses Trailer Frame?

I am of the opposite opinion. I believe anti-sway bars are a necessary insurance. Under perfect conditions, they may not be needed. However, driving conditions can be unpredictable and change in an instant. i.e., extremely strong wind gusts, swerving to miss a obstacle in the road or an animal darting across the road, etc. Driving properly is fine and dandy, but also may require drastic evasive actions when lease expected.

None of the things you mentioned should ever put a trailer in a sway situation. Sway is defined as when the trailer is trying to go faster than the tow vehicle and is characterized as increasing arcs of oscillation. It is not a gust of wind or an 18 wheeler bow wave hitting the trailer for a second and moving it around a little. That is not sway. Your insurance should not be a sway feature on a hitch but the trailer only brakes. That is the only thing that can slow the trailer speed down enough; hitches don't slow the trailer. Think through sway, it cannot occur going uphill, the trailer is drag or trying to go slower than the tow vehicle. It cannot sway. Use the trailer brakes, that is what they are there for if you think you will be having a sway episode. The guys that deliver trailers to dealers from the factory don't use sway features and know that if the trailer has at least ten percent of the total trailer's weight on the tongue, it won't sway.