DD is 13, her best friend is just turning 14.
Bf's parents have been offered 2 free tickets to a (v v big and busy) themepark and have just called me to ask if I'd agree to let the girls go together to celebrate their dd's birthday.
They would drop off in the morning. I would pick up later. The place is an hours drive from home. I would go early afternoon to an adjacent area with my youngest, so would be close by from that point.
DD has been many times so knows her way around. They are sensible but not that used to going off alone.
Buying an extra ticket to accompany them is out of the question as it is so expensive.
WIBU to let her go? If not, what "ground rules" do I need to give her?