<SC1> Before rules, the definition of "Possession" seems impossible. It awkwardly tries to allow very limited forms of pushing (plowing isn't really an appropriate word). It talks about changing the direction of motion of the tribal, implying that a blade cannot cause lateral motion. In fact pushing on the left and then on the right (through steering) has the same effect as a a curved blade. I suspect the intent is to say "When only one triball in contact with the robot at any time, but excludes a robot with a stationary straight blade pushing one or more triball(s)."
After thought.... by current definition, you can only REMOVE one triball from a net at a time <SG8>. My initial thought was a sweep, but that is controlling more than one triball at a time. What is the intent of the game? How do you incorporate removal into "Possession" definition?