Harness seatbelts for Toddlers

While doing a Station Demo today I seen something that I have never encountered. The children that arrived were between 3-5 years old and were from a preschool program here in town where I work part time. As they got off the bus they were all wearing harnesses. These were not your typical kid on a leash harnesses that we have all seen parents have on their children.

These are a 4 point harness that secures them while being transported on the bus.

There can be 3 kids per sear as you can see. These "tether" points are exactly like the ones when tethering a car seat. A little pressure on the latch and you can operate these.

This image just shows that they are attached in the same fashion as a seat belt.

This is front of the harness showing that all they have to do to get them on is unsnap the black buckle, step into the leg straps, placing the arms in the arm straps, and reconnecting the black buckle. Walla!!!

The back is much easier to access, two zippers.








The school director told us that they are required to use these on all children under 5 that ride on a school bus in the state.This was a half bus and at full capacity could carry 25 children in harnesses? I don't believe any children in this age group posses the strength to operate the top two latches to self extricate.
So what would be the best way to extricate these children in a accident?If time was a factor/ not a factor. Would a rollover change that extrication?