Let’s see, what does the Manual say? In this case, Section 7. (This is your “Read the Manual” notice, if you didn’t get one already.)
1a. No limit is defined, explicitly or otherwise.
1b. While “grabbing” is not explicitely defined, “possession” is.
2a. No limit is defined, explicitly or otherwise.
2b. See my answer to 1b.
If there isn’t a limit, there isn’t a penalty. HOWEVER: EMPTY CELLS can only be handled 1 at a time by robots. See <G24-A>.
There is no rule against this, however, if you put it over the trailer, you will get a penalty for blocking the trailer (Update 1). If you entangle an opponent’s robot, penalties may be assigned (<G33>, <R07>). If you go past the bumper perimeter, penalties will be assigned (<R11>, <S04>).
**4. can we put anything over our bot? i.e. a net or piece of sheet metal on the back to prevent teams from wedging balls onto our bot.
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for the 4th question i’d say the best idea is to make sure there is no way for them to wedge balls into your robot. cover your robot up (best with a solid cover so u don’t have to worry about entanglement) to make sure they can’t. Personally, if you are worrying about if an opponent can wedge a ball into your robot, i’d be more worried about an opponents robot getting stuck in there because anywhere those balls can fit parts of the other robots can get into too possibly. Close up the gaps in your robots and make sure there is no part of your where the other robots can easily gain access to that you don’t want them to be there or places they can block the workings of your robot.