Having watched the video, and curled, to me it says little to nothing. Two stones thrown that far apart from one another can show wildly different amounts of curl. Every sheet has it's own characteristics, even across different pebblings things will change. Additionally, sweeping is supposed to make the stone go straighter, that;s the basic mechanics of the game.

I think if they are going to look at putting some sort of rule in place then they need to look at it from something that can be strictly scientifically measured, like the rebound velocity of a golf club face, rather then something against a specific fabric type.