I saw the video on the internet web site and it seems plausible. Around here I have not heard of any boat trailers having that type of problem. Maybe because most of the boats are for saltwater and the trailers may be built heavier.
My tournament partner was coming home from a tournament and had a leaf spring break. It was not a pretty site. It ruined a brand new tire and blistered the paint on the fender. Just so happened that a friend was driving down the same highway (50 miles from home) and hapened to see him on the side of the road. Jacked up the trailer and shoved a piece of 2x4 in there to keep it from rubbing and limped it home.
They are a local company out here and really push their products. It is a great idea but really expensive. I want to say it's around $500. Course that would be nothing if you had to replace an axle!