This person used someone else's electronic credentials to perform a task without asking for permission. [...] This would/should get you fired at many places.
You mean that thing that happens all the time at every office?
I have a post-it note on which my boss wrote his password for me, specifically because he was sick of my asking whenever I needed to be granted access to new things. I can't think of a single job I've that involved computers where I wasn't given access to user accounts that were not mine for reasons of expediency in the face of inflexable permissions systems.