We noticed this on Big MO during the Buckeye Regional this last weekend also. We actually have cylinders that lift up our gripper arms. If we do this with only one goal we tip up seriously. And we we accelerate too fast with only one goal we can get up on an angle. However, we have a
very aggressive track drive system so it doesn't affect us much in terms of traction. When we have two goals and lift them up is when we get the real boost in traction. We are about to drive fine with one goal and our robot tipped up but there is really no advantage to it that I can see.