At this point, glitches and Fallout 76 are something akin to peanut butter and jelly - a pairing so common that it's unusual to think of one without the other.
Players are reporting a bug that fast travels them to Vault 63. It really does beg the question of whether or not Fallout 76 is one of, if not the most, buggy online-only games to date, and how much of the onus falls upon the players to ensure they won't be penalized. Once inside, their group was trapped, and had to fast travel to get out, but they had a poke around while they were inside.
For an unreleased area, Vault 63 seems to be at least mostly finished. Once inside, these players found a spacious, partially furnished vault, complete with overseer's office, wrecked kitchen, and even a terminal reading "Nice Work Assholes" (a possible hidden message for potential hackers?). According to them and a few other players, the Rad-Rat Horde event quest is teleporting players into Vault 63 by mistake.
Obviously, unknowingly accessing an area because your game glitched out isn't something that should be ban-worthy regardless of the game, but there is reason to feel that Bethesda may take a hardline against it.
Thankfully, it looks like there's no ban on the horizon for McStaken and his or her band of merry vault-dwellers.
After almost a day of waiting a Bethesda Community Manager saw the post and stated that they "have shared [the info] with the team". Redditor McStaken was one of these players who got stuck in Vault 63, together with several other players.