Have yall encountered this subversive behavior? And how did you handle it?
Bet you didn't realize when you started this thread that you were volunteering to have your parenting skills, choices and family all analyzed and evaluated.
The way I do it so as not to come off as too overbearing/controlling/commando-ish/freakishly detailed/obsessed is to not have a full-on written plan. I'll just have ADRs and which parks on which days figured out. Then we go along with my mental plan of how to start and then we adjust. As we go through the day someone will say "Oh let's do this!" and then the wheels turn in my brain and I adjust the rest of the plan. In fact sometimes I'll be the one to say "ok next we could ABC or DEF" and let the group decide. In your situation you could build in some times like that. "Why don't you wander while we do KJ Safari, fastpass EE and we'll meet you at Dinosaur?" See how many times they decide to just come with you anyway.