I do not think by hitting other robots in practice is a good thing. practice is to work out your bugs of the robot and you can not do that by getting hit from other robots. I can see the last practice match you might try to push another robot to see how you stand up to them but to do any harm in anyway to the other robots during practice is very wrong.
You have to wait until the real game to show how strong you are
We do like defense but not during the practice round avoid any contact if possible but if hit then all bets are off.