I know its a different world legally sometimes, but Kongfrontation this is exactly what happened, only 30 feet in the air. A long Lap Bar with children seated in the middle would be the only restraint that would make sense. That being said, I don't think there is one.
Sea belts would be a capacity nightmare with capacity and operations to get everyone buckled in within a row you can't walk down.
The motions and jolts as said are on platforms similar to Earthquake's original motions. Which if everyone remembers, had no restraints.
I'll agree it likely won't have restraints - but the number of people wouldn't pose a problem for seat belts. Simulators solved this long ago - they simply have an LED grid that matches the seat layout. They turn on the seatbelt system (usually an vacuum system) and then watch for all the lights to come on. If one doesn't you have that person redo their belt.