Okay, I just want to know if I'm right on this, but if a fic is something like Percy Jackson and set in America with American characters, they use American terms but if it's Dream SMP from Tommy's perspective or Harry Potter or any other British character, they should use the British terms for something.
For me, it just ruins the emersion when Harry Potter walks across the sidewalk and into the eye doctors instead of walking across the pavement into the optometrist.
It's just basic fanfiction etiquette, right? And also it's common sense.