I use an Acme EZE Tow Dolly with the surge brakes. The surge brakes will activate when you slow for any reason, whether it's the service brakes, exhaust brake or down-shifting. It doesn't give me any problems with the mountains around my home in the Smoky Mountains. However, when you are planning on going down a long descent, you can insert the supplied key to lock out the surge brakes.
It's not a huge concern, even if you don't lock them out. The brakes are well ventilated, so they cool well. Also, the brake pads are extremely easy to replace if you wear them out.
