Lets add it up... Bike ~ 40 pounds + trailer ~ 25 pounds + rider ~ 200 pounds = 265 pounds. I have an almost identical trailer and you are not suppose to put more than 60 pounds in it; but lets say they somehow can fit 150 pounds of wet compost into it... that is still only 415 pounds. Our mountain bike tandem has the same type of brakes. It weighs 65 pounds, I weight 200 pounds and I have ridden it with a 200 pound stoker on numerous occasions. We never had problems stopping. Someone doesn't know how to adjust their brakes.
I said I doubted the 800# part.
400 sounds much more reasonable.
What can we expect from modern “journalists” but hyperbole in order to push the agenda.
Too many people will take the 800# figure at face value.
An empty tandem axle U-haul trailer scales in at 1600#. The maximum load ed weight limit is 5000#. The trailer has surge activated hydraulic brakes. If one uses that as a reference, a linear scaling factor would approximate about 160# for an empty commercial duty trailer built to the same standard for this task, as depicted by the article.
Bikes built for commercial purposes likewise are of heavier construction than two wheelers for recreational use. The trailer and load are probably twice the weight of the bike and operator. The hitch mechanism should have a force sensing system with which to apply electric trailer brakes if the load is of that magnitude. YMMV.