I think it depends on the moment it happens. When I managed a larger team I could get a bit of communication overload. I'm trying to juggle ten requests at the same time, prioritizing who/what needs answering/updating and generally making sure I am unblocking anyone/everyone.

So when I see "Hey" I rarely see it as polite. What I'm thinking is "What do you want!? Spit it out!". IMO, politeness would be something like "Hey, I have a question about X, is now a good time". That at least I can prioritize. All I want is a tiny bit of context to the "Hey".