Hello, can I sit here?

“Hello, is there a seat here?” That’s a pretty daft question when you walk into a train compartment where there are six seats and four are free.
That’s exactly what happened to me today, and it’s no exception. A bloke came in, opened the door, asked, stood in the doorway and stared at us like an idiot. He probably wouldn’t have sat down until he’d been given permission.
So many times I feel like saying: “No, we don’t, it’s fully occupied here, get lost!”
Not so much because I mind people, but simply because I’d be curious to see the reaction of people who need permission to sit in a free seat on a public train.