Orr wrote:
To approach a group of people, for instance at a place of employment, and say, 'Hello. What is going on here, please?'
I am by no means the expert on social interactions, but here are my thoughts.
Approaching a group of people is fine. Talking to them is fine. I think you have to word your opening sentence differently, though. When you say, "what is going on here," it sounds a bit like an accusation. I think that, yes, that could be interpreted as rude, even though I don't think you mean to be. I would recommend, "What's up?" or some synonymous phrase instead.
I'm assuming that you do mean to strike up conversation with this group of people, not accuse them of something, yes?