I can't get over the fact that the OP's child was still in the daycare center at 10pm. This isn't like home where the parents go out for an evening leaving the kids with a sitter in their own home where they feel safe. This is leaving your kids with strangers in a strange environment at a late hour. I feel sorry for the poor kid.
And the three year old was simply acting like a three year. The kid was probably confused so he wanted his parents close by. I don't think it was the responsibility of the day care people to convince the child he should stay with them.
It appears the OP was hoping for a vacation with hubby depending upon dumping her responsibilities i.e her kids on the cruise line. I'm sure if her 3 year old was taken to a room and put on a mat to nap as she suggests, he probably would have screamed bloody murder.
Next time if she is still able to take a vacation, she needs to leave the kids at home with a trusted sitter or bring along her own nanny if she wants to behave like she is unencumbered by her children.
A refund? I don't think so.