As noted above, just because you can pull something with a smaller vehicle does not mean that you can stop it or turn it in an emergency. Typical case here in KY is long downgrade, lots of traffic, come around a bend, and suddenly everything in front of you is sitting at a standstill. At some point (under 7K lbs?) the trailer is not required to have trailer brakes, so, it is all on the tow vehicle to maintain control. Your tow vehicle either has the azz to manage the emergency case as well as the normal case, or, you're gonna have a sucky day...
Most states require brakes on anything over about 2k LOADED. Idaho is different. They require them on any trailer over 1500 EMPTY. That's dumb. You can get a an empty trailer with tandems that still weighs under 1500 but can carry several tons. You can get a loaded trailer that weighs 6 or 7k and still not need brakes.
