Ok, I KNOW this is unlikely, but suppose one or all of the Animorphs had decided to tell their parents sooner about the alien invasion and their part in it? I know they (rightfully!) assumed the 'rents would have either forbidden them from taking part or gone to the police and exposed them all, but just suppose they did tell them. We SAW what it looked like for Cassie's parents, and Rachel's, and Jake's... well, we never his parents' reaction. Here's my theory on what they would have done based on the available evidence.
Cassie's parents would have gone along with it, I think. Then again, they only went along with it in the books because they were onto them and they had to move fast, so I could be wrong...
Jake's parents could never have lived with their son being a Controller and not doing anything about it, especially his father, so I think had Jake told them, they would have done something (I don't know what) with Tom, something that involved revealing the truth, thus exposing him as one of the "Andalite bandits" and causing the end of the Animorphs.
Marco's dad, I think, would also have gone along with it. Also depending on when Marco told him, he would have been heartened to learn Eva was alive. I think it would have been a nice alternative to #35. Instead of taking option 1 Let Dad remarry or option 2 Don't let Dad remarry, he takes option 3 Tell Dad the truth.
Rachel's mom would have gone to the police, end of story, and thus exposed them all. If she believed it. Her father probably would have helped her, discreetly I am thinking, in fighting the Yeerks, and supported her.
Well, what are your guys' ideas on this?