[Al Skierkiewicz]

How about we look at this in a practical light. The velcro has a distinct adhesive property based on matching a particular type of "male" and "female" material. The strength of that adhesion is proportional to the mated area of the material. When mated with material other than that for which it is designed, bad things occur for both materials. Additionally, when it does produce friction with the floor, the force needed to pull it along the carpet is also very high. While everyone has admitted that the "male" velcro does pick up fluff, remember that it does not give up that fluff readily. At some point, (within minutes I suspect) the contaminant will have reached a point where the material is filled and all friction is lost.
In the case of wheels, the mated surface area is quite small, less than 1 in^2. in most cases. I would suspect that the coefficient of friction to be quite small.
What would determine carpet damage in my mind is watching the robot drive across the carpet. If it leaves a visible trail, I would say it is damaging the carpet. If it picks up a considerable amount of fluff in a short driving session (say one match), it is also damaging the carpet. In this case you will have a harder time with the FTA and Field Supervisor than with the LRI. They can prevent you from playing until you correct the problem.