I think OS miss the ability for an admin to log into a user context. I am very hardline defender of privacy and in principle I support privacy advocates already

I think OS miss the ability for an admin to log into a user context. I am very hardline defender of privacy and in principle I support privacy advocates already preparing my pyre for even suggesting that of course. But if we are honest an admin can already access relevant data anyway and you do indeed need to use a user context to access certain settings of some applications. This is especially true for less digitally affine users. There are workarounds (Windows->Run as...), but that is sometimes insufficient. About an admin using your user account to start the nukes? That is mostly possible anyway in the usual corporate Windows configuration. He could just change your AD password and log in as you. I would recommend that approach anyway and then force the user to set a new password and informing him why you sabotaged his workstation would also be nice. Far more secure than having the holy grail Excel file.