well in the strategy team we brainstormed about all kinds of defensive strat's
the backbot, on all our strategies collected balls all the time
but we had a few ideas for him
for example have the backbot pile up lots of balls infront of the corner goals
and pick up ALL balls from the field, arranging them according to the teams capabilities, also during the defensive period our HM's will throw balls continusly towards the bot for him to organize the balls
one of the most important thing is we control ball circulation,not the other team, that way they need to wait for us before they can act
heck if we have a lead when most balls are in our side we might not even throw balls out and just wait out the rest of the match, always think about the circulation VERY important
about the 2 other bots they will try and push balls away as much as possible
if the opposing team has 2 pushers and one shooter (Average?)
if the pushers get the balls in the corner goals we can let go of them and focus on the shooter (since any ball coming from the HM's on the other side will be quickly pushed away by us, easier to push a ball and disrupt collection
then collecting a ball...
we are trying to get a meeting with some basketball coaches on more defensive moves and strat's seeing as this game is VERY similiar to basketball
in the gameplay
and that's about it, wont get into specifics (

) but I do suggest
you guys take photoshop or even PAINT or whatever and take the arena graphic (from above) and draw up moves your bot might do on the defense
study them
and offer them to your alliance teammates in the matches
only trouble is trying to convince your alliance to go with one certain plan
and not just "play it out"
good luck all
(my 2 cents, sorry for typos)