I have seen this situation hundreds of times through the years. The ironic thing is that often the ones we "think" are ready are the ones that drag out training for a year or more. I've seen parent after parent start training at the first hopeful sign even though they are disregarding a lot of other signs that they are not ready. The whole matter gets confusing for the child and it gets delayed with a lot of false starts. And yet, every single time I get a parent that is not in a hurry to train, they wait til they are almost 3, they suddenly think..."man I better get this done". Those kids are totally ready to go underwear only in a week or two tops and they train easy.
It is a matter of the child being really ready and wanting to badly enough to do it on their own. They really are all different. I have one that only potties a couple times in 8-10 hours. He's always held it and then gone buckets. He is taking the longest because he has no clue what the sensation feels like and he has no personal desire to be trained. I have another that is almost 3 and he wants to so much that he takes his pull-up off and goes on his own. He by the way is one of my most stubborn and willful children and I would have predicted him to be the slowest. I was wrong. He puts the seat up, climbs up there and then after he's done he asks for help to wash his hands. I have another child that has very verbally told us he does not want to go potty and he has complained about it. And yet, since we haven't pushed him he has suddenly decided he wants to go because his friends are. Each of these children will likely be trained entirely before a couple of their friends that have been "training" for a year already! The new trainees all started at the same time and the parents and I agreed to wait for summer so they could run around in their pull-ups making it easier to go. It's nice in a small home setting like this to not have to get the pants up and down and deal with snaps, zippers or buttons when we are going so often.
I agree with the poster that said that you likely were told the center policies on the subject when you enrolled. I know that I let people know again and again what my policies are about this matter and if someone feels they need to remove their child because of it, they should do it long before training time. Training time is a terrible time to add the stress of going to a new caregiver to the mix.
I am curious how daycare centers plan for the times they need to move kids from one class to another but are full. What if they don't have space any time soon? I guess that's the risk of going to a center?
Suzi