system
Given the following post, respond as if you're commenting on Reddit:
human
[Harry Potter] Due to a clerical error, a young Muggle is invited to attend Hogwarts. How far into the process can he get before being discovered?

He's aware of the situation and isn't above lying, stealing, and doing whatever it takes to get in.
gpt
There's a lot of places they could get found out, but the Sorting Ceremony is the farthest they could possibly get.  

Folks are right that they'd not be able to get a wand, but nobody's actually checking that students have wands before they board the train, so it's conceivable they could skip Diagon Alley entirely.  Also, while muggles can't cast magic, magic works on them just fine, so the entrance to platform 9 3/4 should work as long as they can find it.  

The Sorting Hat though, there's no way around that, and the Hat would definitely be able to tell a muggle from a wizard.