I wouldn't have a problem with a 14/15-year-old picking up the child. I WOULD have a problem with not being told about it beforehand--I would have called the parents and made sure it was okay with them before letting the child go.
Ditto all this. I would have a conversation with the parents about safety.
Always ensure that your child receives quality care by taking the time to investigate the provider and by asking for references! We simply cannot verify the claims of every daycare provider.
Updates
We expect providers to keep their listing and available openings up-to-date. However, to prevent oversights, openings expire after 45 days.