Eh. The entire state of Oregon gets by just fine without absolute ballot secrecy. And any other state that largely or to a significant degree exercises no-excuse vote-by-mail. Basically everyone in Oregon votes by mail. There are in-person voting booths at each county election office for the few oddballs that want to vote in person, but almost everyone votes by mail. It's October 22. My ballot is already in. I've already voted. I filled out my ballot in my kitchen.
There was nothing physically preventing someone from forcing me to fill out my ballot the way they want to. There would be nothing physically preventing my employer from saying, "fill out your ballot the way you want in front of me, sign it, and then give it to be to turn in. If your refuse or cancel your ballot later, you're fired."
Yet that doesn't happen. Why? Because we made it a serious fucking crime to do that. If I'm reading Oregon law right (I'm no lawyer), coercion of a vote that way would be a class C felony punishable for up to five years in prison and a $125,000 fine. And I'm less sure on this part, but I imagine that would apply to every single employee you coerced this way. So you're risking a felony for ever single vote your coerce. That's a huge risk for a single vote. It's just not worth it. Some real morons might try it, but no one with two brain cells to rub together is going to give it a try. Plus any federal penalties.