[David.Cook]

Let me debunk that theory...

A stack of two can be easily undone. What is happening is bots are just running into the base bin full speed from a few feet away and they go flying. Also, the side walls help cause motion when bins are rammed against them.

One example from VCU, with 15 seconds left to go, our bot was hung up on the side rail. We got loose, rammed the stack to break it, wheeled around from the corner of the field and made it onto the ramp to hear "2, 1, times up!"
(I don't mean this boastfully... we were all sweating bullets at the time. I don't believe our driver pulled it off.)

I do agree with you, that if you can stack three or four in 20-30 seconds you can swing a match. Provided there are enough bins left in the scoring area. It seems a fair number are getting knocked out of the playing area.

CORRECTION: My son reminded me that the Robodogs were able to pick up a human player stack of four and placed it on another bin to make five, then they repeated that to make a six-high stack. This was during a qualifying round.