Not all surge break systems have the electric bypass. Older ones sure don't, and most of the ones here at my lab don't. Depending on the design of the surge brakes, a penny may not work. Some require a bolt that passes through one or two arches. I keep a bolt for this purpose in the cab of my trucks, since this is more common here than the kind that work with a penny. If you are trying to back up over rutted gravel, it is as bad as backing uphill, or worse, especially if you are trying to stick the boat in a tight place. When those trailer brakes kick in, you can't steer. And I used to have to squeeze my big boat into a barn door only 6" wider than the boat, uphill over a gravel parking lot. I'd have lower the motor to get the tongue inside the barn door too. The rig length (truck and trailer) was a hair under 50 ft, and the distance to the pond in front of the barn was 55 feet. Not the kind of job you leave to the new technician. And you better believe I used the bolt in glove compartment every day.
There are a lot of designs for these surge brakes, but many of them have an extra wire that is designed to hook onto the truck and cause the trailer brakes to lock up if the trailer comes off the hitch. If that system ever engages on you for whatever reason, after you clean your shorts and get the truck and trailer hooked up again, you will probably need to chock the tires and back the truck a bit to compress the cylinder before you can get the lever that locks up the brakes back into the running position. Otherwise you will be dragging the trailer home.