The Master Key unlocks most rooms in the building.
The Master Key does not unlock:
                               The Gender-Neutral Bathroom

                               Exterior doors 

                               Lockers, Safes in rooms

                               Lockers out of rooms

                               Mechanical rooms (often found in the hallways and sometimes have a buzz coming from them. They usually have two doors as their entrance.)

                               SOME storage rooms



The Bathroom key unlocks the Gender-Neutral Bathroom.
The Bathroom key is assumed to not unlock ANY other doors in the building. There will be more testing taken to confirm and figure out how accurate that is.




HOW THEY COME:

The keys will be copied onto Key Blanks in the game and will have an embossed "Do Not Duplicate" and/or "U.S. Property" on them, so key copying stations and NPC thieves cannot steal your key and copy it without being caught, and you will get the key back. 

           (They cannot copy it after they steal it)

If you try to copy the key, most stores will not let you as it has Do Not Duplicate and a more threatening embossment, "U.S. Property". It is illegal to copy keys with "U.S. Property" on them, and the cops in game will be notified and arrest you. 

This will make you lose $500 and the key.