from what I have heard, even if your child doesn't behave well (ex: cry and cannot settle down), they will invite you back for a 2nd chance in another day (not sure if it is true or not).
We went to the play session two weeks ago. They just asked the kids to play and they talked to the parents casually one by one. In the end there was a story time and they gave everyone a sticker after that. Then the principal said 'everyone will get an offer' before we left (around 8 kids).