Do you stand?

Apologies if this has been raised before, but I could not find a discussion on a quick search.
I flew economy a few weeks ago and observed something I hadn't really taken notice of previously...there was a queue of Upper passengers lined up by Door A. Although the gate area was busy there were seats available, yet they stood there for a good 10 minutes before boarding commenced. I thought it was odd; almost like they were standing just to make the point that they were in Upper.
I've only flown Upper once (never did get around to doing a TR), and I made the most of my time in The Lounge (LHR); most everyone had boarded by the time I got to the gate.
So, my question is, if you get to the gate before boarding starts, do you stand or do you sit?
I flew economy a few weeks ago and observed something I hadn't really taken notice of previously...there was a queue of Upper passengers lined up by Door A. Although the gate area was busy there were seats available, yet they stood there for a good 10 minutes before boarding commenced. I thought it was odd; almost like they were standing just to make the point that they were in Upper.
I've only flown Upper once (never did get around to doing a TR), and I made the most of my time in The Lounge (LHR); most everyone had boarded by the time I got to the gate.
So, my question is, if you get to the gate before boarding starts, do you stand or do you sit?