In my experience it is pretty common for people who bring work home with them not to be super-meticulous about preventing access to the content of the work by their families. How many people do you know who sound-proof their home office so their wife can't eavesdrop on their business calls?
I think I should point out this is a fireable offense in a number of companies. I work with sensitive information every day. I'm pretty sure if allowed someone outside the company to use my machine for anything, I would be fired.
My dad works for IBM doing mainframe repair and installation. He's seen his coworkers fired for allowing unauthorized individuals to use their company laptops. They've gone even further in the last few years in making unauthorized software a fireable offense.
Granted, two data points isn't a lot but there are companies that have enforced policies to prevent sensitive information from leaking.
I should also point out both my dad and I do significant amounts of work from home and we are both required by our companies to use full disk encryption.
Without going to the extreme of secret+ classifications -- in which case you cannot take things home without a secure home office, and move things between them in secure containers -- I don't think employees are fired for failing to lock their home office against their spouse or soundproofing their office against their spouse.
Which is different from saying that the company would fire them if the spouse used their inside-access to harm the company in any way.
My girlfriend works on disclosure projects at a company you've heard of and who regularly has highly-anticipated announcements. I have no idea what she works on, even when she's working from home in the same room as me[1].
I think that people that can and do bring work home are employed in fields where one does not need to be super meticulous about preventing access to the work.
Depends on what you mean by SCIF. Coworkers bring confidential paperwork/documents home, and remote access over remote desktop software is blessed. However you might get a phonecall from security if you started downloading lots of confidential data directly to your home computer.
