Alt accounts aren't really an issue on PC the way they are on consoles. You can make an endless amount of free accounts on Xbox and Playstation, and as far as DayZ the game is concerned, (and most other games) those accounts belong to a different person.

It's a unique problem with DayZ specifically because of how DayZ works, and people frequently use alt accounts as pack mules.

For the new Livonia Bunker, my concern is that players will log out inside of the Bunker with an Alt Account, and have a permanent way to unlock the base for themselves or their teammates, bypassing the punch card system entirely once inside.

Suggestion: Implement a system where logging out inside of the bunker boots you to another location upon relogging, similar to how dynamic gas spawn zones relocate you. Otherwise, the entire novelty of this thing being hard to enter is going to be worthless.