Definitely needs to be braked!
Have towed a landcruiser on a single axle trailer with a FWD V6 Maxima no problem. But loading and unloading is REALLY interesting.... the back of the maxima is too light, and it gets lifted off the ground!!!
Not really ideal.
I had the same problem with corolla towing starlet on the same trailer. But the towing was really dodgy, I had to abort and swap to the maxima, it just felt unstable, the corolla was far too light.
So I reckon a single axle trailer is okay, as long as your tow vehicle is heavy enough.
Never used a tandem.