We use OfficeVibe, and I have full employee access. There is absolutely no feature anywhere that shows me who submitted a comment. I could just about hack one together by putting each person into a one-person team, but the user would be able to see that themselves. Sure, we can imagine a conspiracy where my CEO has a special button, but I strongly doubt it.

That said, it's still frequently obvious due to people's writing styles, the nature of their complaints, timing.