Yes, they can. If you piss off a moderator they'll just ask an admin to ban you, assuming it's not an admin's alt in the first place (admins have sockpuppet mod accounts on every major sub)

They just use the internal tools and create a ticket to have an admin ban your IP and all current and future accounts. Wow, such a hurdle!

Even more awesome to have this happen with a dormitory IP. /s