Okay, this is something that we came up with at the beginning of build season but never used it (blocking is not in our strategy). The perfect blocker would be a large pole mounted on the edge of a lazy-susan turn table. When you wanted to block you have a motor turning the table and the previously small rod now takes up close to three ball widths (or more) Couple this with rapid robot movement and it could become a very effective blocker.
https://encrypted-tbn0.gstatic.com/i...IXJv_Fw3vy9vRv
The table could look like this and you mount the pole on one of the corners. (the table would obviously be bigger).
Figured I would share the idea for anyone who wants a blocker. What do ya' think?