[KeithInSpace]

Have no idea how sway control works, but I've personally seen utility trailers swinging wildly/violently from one side to the other. In both cases, they were overloaded vehicles that weren't generally suited to towing (cute-ute in one case, green wood-sided station wagon in the other).

In both cases, the vehicles were loaded in addition to the loaded trailer, greatly lowering the ball such that it was much lower than the axles.

It is my (limited) understanding that you ALWAYS want the ball up and the trailer flat or "sloping back", even when loaded, to combat sway as a result of bad towing geometry.

Sway because of wind is a whole different monster, but I am 100% certain you can have loads of sway with a low profile trailer in no wind.

That would further the argument that WD hitches are a first line of defense against sway. They promote proper geometry at the ball.