According to that *pertrans* link, which is sponsored by Xootr, all bike frames which received lower stiffness ratings, you will notice, have a folding main frame; bikes with the highest rating, regardless of material, are bikes in which the main frame does not fold. I've been told that although Raleigh 20s have folding main frames, they're pretty rock solid bikes. In other words, I'd definitely consider what the source is saying, but would mix in my own real world experience.

As far as the Merc bike, Brompton has already shut them down (via potential legal action) from being able to sell in Europe and in Asia as well, I think. But again, they'd only go after businesses that were trying to make a profit off of their design.