if red alliance is not double zoned and they are pushed under their goal by a blue alliance robot and they have no choice but to descore some of their triballs on the way out. would the blue alliance robot that pushed the other into the goal get a penalty? The blue alliance robot technically didn't descore the triballs, and <SG8> has no mention of this strategy. Also, if the red alliance robot gets stuck in their own goal after a blue alliance robot pushes them in and blocks the exit, does anyone get a penalty? <SG8>
descoring your own triballs
There are no rules that prevent the interaction you've described, unless the blue Alliance Robot enters the red Goal in Violation of rule <SG8>. De-scoring Triballs is neither defined nor prohibited by the rules.
If a Robot becomes Entangled during any interaction, including the one you've described, they will be subject to a Disablement as described in rule <SG5>. In your scenario, if the Head Referee determines that the Entanglement was caused by the blue Alliance Robot, the blue Robot will also be subject to (at minimum) a Disablement and may receive other penalties at the Head Referee's discretion.