Hmm. I let my DD go to one at the same age. It was during the Rugby World cup in NZ and Wales had reached the end stages. I knew all the children present but still spoke to the host parents.
Their solution was to have a (huge!) scout-style tent in the garden which could be sectioned off. Mum slept in a partition and dad in a single-man just outside. They made the boys change in the tent & the girls in the house. There were also a pair of bolt-bedrooms in the house, supervised by the grandparents, for any of the children who were uncomfortable with sharing or who didn’t like the tent.
Apparently they were telling ghost stories until late. The tent was patrolled at regular intervals (but not timed ones, just in case ). They also confiscated all electronic devices and locked them away.
I had an extremely tired DD the next day but she thoroughly enjoyed herself.
The parents and grandparents were knackered, from patrolling all night, but felt it was worth it.
So, my take - find out what the arrangements are. What supervision will there be? Is there somewhere a child (of either sex) can escape to - that is also supervised- if they are uncomfortable for any reason?
Would the host parents like some additional support?
Talk to your child. Discuss whether they would be confident going to the supervising adult if they were uncomfortable with something.
If you are happy with the above & you trust your child then fine. If not, don’t let them go. Either way, your child, your decision.