AnKa:I am a parent and if my kid was transported without a car seat for a DRILL I would flip. Especially in the chaos of a full blown drill.
In a real emergency, all bets are off.
But, Anka, if your child was killed because she wasn't properly restrained surely you would place that responsibility on the center, whose utmost goal is to provide safety for the children.
Of course you would want them to do what is necessary in an emergency, anyone would think that. However, if they were negligent and breaking the law you better believe there would be consequences. As a former teacher and now administrator there is no way I would put that liability on myself. I would much rather walk down the road (even in the road if I had to) with my students rather than transport a minor in my vehicle.
As for the children with limited mobility, my suggestion is to buy a large enough stroller or a multiple child buggy and push the ones who can't walk in that, just like infants have a emergency crib. Get everyone out of the building, load them up, and start walking.