Nanny drove my child to the park without a car seat

She’s allowed to take my child to the park, but they always walk there. This time she decided to drive there, which I’m okay with, but she didn’t have a car seat! My 4 year old told me pretty clearly today. The park is literally .02 miles away from the house so it’s not far, but what would you do if this happened? Wish she would’ve just told me.