"With Celestia as my witness" · 10:16pm Feb 26th, 2019
From telekinesis to rewriting reality, magic in the MLP universe can do a lot. There is an entire branch of magic affiliated with crystals and the mind called "dark magic" that's completely forbidden for anyone other than Celestia, Twilight, and (presumably) Luna to even know about. I'd also say that Equestria is not free of crime, though crimes of the more ugly sort are likely much rarer. Still, when a pony's future hinges on their innocence Celestia is likely to be called in.
Here's the thing: Celestia won't share any magic that can be used to alter or view another's thoughts. To the judge, her way of determining innocence is a complete black box. The only way the judge knows that Celestia isn't making it all up is trust.
That makes her a witness.
I like this concept.