In Pennsylvania a safety inspection is required each year. That inspection requires that one drum be pulled from each axle to check the condition of the brakes. Many totally ignore maintenance procedures for drum brakes that have been around for about a century.
I have found a brake magnet that wasn't connected from the factory, magnets that caused deep grooves in a few thousand miles and bearings that were poorly manufactured and were failing in one season. If you don't know what is in there, maybe you should check.
Yesterday a utility trailer crossed right in front of me and ditched it on the roadside with the wheel smoking. Maybe he didn't know what was in there.
Good Luck, if you depend on luck.