Electronic sway control trailer option?

In my application, it certainly isn't a placebo as suggested above. In a few situations where I never touch the brakes and a bit of sway starts, the system pulls me right back in line. It can be felt and when the system gets aggressive enough, you can briefly smell the brakes. It's not a gimmick. That said, it's also not a requirement. People have been running without a system like this since the dawn of RVs. For it's extremely low price, I'm glad I ordered it on mine though.