It's actually a good question, as long a character are 18+, I don't see why it would be a problem as long as it's realtively explicitly stated. We can start by allowing it for now a revise it at a later time if that becomes problematic in one way or another.
Which reminds me that I should update the rules, haven't had much time this week and the app is not really useful for this!
i dont see the problem as long as it's explicit that it's 18+, but if you had to make this post, surely you can sort of see how it might hint to underage.
I feel like it would have to be a case by case basis, but almost always not okay.
I think the question to ask is: How important is the fact that the character is in high school specifically? Why is that important, and would it be meaningfully changed if you just said they were a freshman in a small college or university?
For example, do you want to play our a scene between two 18 year old high school seniors getting together after their senior prom? I think that would be totally fine and is a reasonable scene.
A teacher/student fantasy? Would it be that different if you changed it to teacher/student in a college setting?
The main issue people will have is the usual range of high school students is 14-18 years old. So 80% of them are underage. While in college, you're almost always running into students who are 18-22 years old. 100% of legal age and no issues.
I'd be interested in hearing your thoughts. I genuinely feel like almost all high school style prompts can be changed to college with 0 effects on the scene.