This is the car he is referring to:
http://en.wikipedia.org/wiki/Chaparral_2J#2J
A similar idea was also used in F1 at one point:
http://en.wikipedia.org/wiki/Brabham_BT42B
As for why he thinks they will damage the carpet, I really don't know. I have heard that the slick material is flexible, but I can't imagine that the amount of suction that could be created by a FIRST robot could damage it.