Yes, I would like to see the source that makes the claim that Reddit doesn't shadowban, because any mod of any subreddit can trivially refute that. I see shadowbanned users all the time, and Reddit calls them shadowbanned in the UI; it's not a secret. Nearly all of them are fairly new accounts, presumably having run afoul of some sort of automatic system. It definitely has plenty of false positives, but at the same time I also see essentially zero spam, so it's clear that they're trying to optimize for false positives rather than false negatives. It would be great if mods could at least approve a shadowbanned user for posting in their own subreddit, right now the only recourse is for them to make a new account and roll the dice again.