Does Disney have an age for letting kids ride without parents? I'm wondering about this because on occasion DH and I won't want to go on a ride (Mulholland Madness

) and I'd be willing to let them go on it alone. I do have a 12yo very responsible DS that I would let have a little freedom in the parks and to watch over the other 2 on that ride, but I wondered what the "policy" is about riding without parents. Anyone know?