Team 230 started out this season with 2 feet covered with velcro that we could push down on pistons to prevent being pushed. We used them at the Suffield Scrimmage but they did not pass inspection at our first district event in Groton. In fact, we replaced the velcro with rubber and they were still not allowed. It was believed that they would damage the carpet so based on both R6 and G10 the feet had to be removed. (
In the end it was all good... as we won the event so I guess we didn't really need them. 
)
I recognize that feet are not the same as wheels, but when being pushed in a direction orthogonal to the way the wheels spin, they provide essentially the same traction and forces on/risk of damage to the carpet.
My point is be careful in what you believe to be legal based on one event or one inspector. I definitely agree that it is probably better to try to get a ruling from GDC on the Q&A... and if they respond with a "cannot comment on a specific design" then definitely be prepared to remove or replace the possibly offending wheels (or feet in our case).