The inline devices such as the Curt Echo engage the trailer brakes whenever the vehicle brake lights turn on. As all active vehicle safety braking systems turn on the brake lights when they function the trailer brakes will also be engaged during vehicle initiated emergency braking maneuvers. I've seen more and more of the Curt devices and it makes me wonder - do you keep the app open on your phone when towing so you can manually apply the trailer brakes if required? I usually use my phone for mapping so I'd need a second device for the Curt Echo. If I was going wireless I'd lean towards the Tekonsha Prodigy RF.