I would allow

My teen went to an overnight at a friend’s house on Monday because they were off this week.
Either you are a sleepover-allowing household or you aren’t. There seems to be a huge divide. I trust my teen to make good choices and since they are a senior and 17, it’s time to start trusting that I’ve raised a decent human before college sneaks up on us.
I’m happy she has a good group of friends who are high achieving in high school and seem polite and kind.

We try to say yes as much as we can. Our oldest is only 13 so no mischief yet but will keep an eye on that, as we are entering new territory these days it seems. That being said, we did say no this week as we have family in town and want the kids to be somewhat rested to enjoy this rare family time. Now that the weekend is hitting I'll be fine with it.

I always allow this. My high school freshman has been doing sleepovers since 5th grade and has never gotten into trouble and has a great time. He has definitely been tired and sometimes missed things because of it, but nothing worth giving up the fun of sleepovers. He is only a kid once and I want him to have as much fun as possible so I always say yes if I can. He is very organized about his work and gets straight As at a rigorous school. If that was not the case, I would re-think my approach.