Yes, I don't know if walls are the right word, but sometimes if you look closely you can see a soundproofing curtain rise up before you enter a scene...It blocks sound from entering the wrong scene
Look up after the giant alien scene in MIB, you can see one up in the ceiling, and at the beginning before the training scene
They are great ways to keep sound in specific areas, but, anything in front of a ride track must be fully clear before a car can get close...I believe many of them were turned off to increase capacity
Nowadays rides are built with better sound proofing and more sophisticated on board audio, so it's not a huge deal