There may be no windows and no doors, but Disney believes those under the age of seven should have an older guest sitting with them when they ride the Haunted Mansion or Toy Story Midway Mania. From TouringPlans.com:
Beginning Monday November 5, 2012 the Haunted Mansion and Toy Story Midway Mania attractions in both Walt Disney World and Disneyland will temporarily testing a new seating policy for the rest of the month and gauge guest reactions.
According to the new policy, children under 7 years of age must ride with someone over the age of 14 in the same row. The previous Toy Story Mania policy was that an adult must be in the same vehicle. There will be a sign near the entrance informing guests of the new policy. There will also be Cast Members at the ride exit surveying guests about how they feel about the policy.