Being a politically incorrect type person, I question a lot of assumptions that everyone else just goes with.
I have a heavy DP (with a retarder and air brakes) and tow a light Jeep Wrangler with it that does not have any additional braking. I've been to Alaska and back, in the steepest mountains Canada has, over the Continental Divide I don't know how many times, entered the Tetons from Idaho, had 14% grades in Utah and so forth. So far I haven't found anything that was at all unsafe for my set up.
As for the toad coming unhooked - we'll, there's a strong towbar holding the Jeep and two very strong aftermarket safety cables. There are other things that are more likely to happen than this.
Some people will site your domicile state laws dictating what you must do. I've looked mine up and found one place saying I must have brakes on what I'm towing if it weighs over 5,000# and another place saying anything over 10,000#. Either way I'm well within those limits.
Bill