One might find a brake has over tightened itself by seeing smoke coming from the effected wheel while stopped at a red light etc. It is almost impossible to detect from the tow vehicle while at road speed as the smoke is quickly dissipated by the wind , and the distinct acrid smell of hot brakes is dissipated behind the trailer .
If it lasts long enough the brake will overheat to the degree that the inner grease seal will fail and the hot grease in the bearings will sling onto the red hot brake drums and burst into flame .
It will then be VERY noticeable ! :-(