I agree that reviewers should do it. I don't think the companies really want to be called on their claims, but if a reviewer wants to put those phrases out there then they should back them up.
This is the only reason I could think of that a company would not want to publish the data. If Libs basalt "HP" scheme only knocked off 10 grams... no one would pay 200 more for the upgraded board.
I just think review companies should sack up and weigh some shit. It would be so damn easy...
Thegoodride.com has the closest I've seen and actually gives equipment up to 5 stars based on weight, but thinking about the difference between a 3 and a 4... it doesn't really help much.