It doesn't happen much anymore, but when I first started to seriously fly on United over five years ago, I was often told:
"This line is for First Class passengers."
"It's not your turn to board yet pal."
"Son, we're only boarding elites right now."
"Hey. You're in the wrong line."
And when I responded that I was in First Class or I was an elite, I would be met with incredulous looks and even the occasional quips about how I stole someone's upgrade.
Well, now I run into situations where it seems obvious that passengers are in the wrong line or are not boarding when they should. Even when I can see their boarding passes, though, I mind my own business and let the gate agent handle it.
This supposed first-hand account I read on Flyertalk clearly demonstrates why all of us should be always be careful not to make assumptions.
I observed the following on UA NRT-ORD:
Loud young well-dressed woman speaking to scruffy-looking older man:
LYWDW: "You can't be here, this is for First Class and elites."
SLOM: "I would not want to 'doscomfit' you, young lady, please go ahead"
LYWDW: "OK, but you should go to the Economy line."
SLOM: <not another word>
Soon after a UA employee came up, addressed SLOM "Please come with me Mr. President, and I will escort you to your seat. We have already loaded your carry-on bag"; to the LYWDW "Excuse me, Miss, while we escort President Carter on board."
Not only had he been standing there like any other passenger, but his invisible security were never visible. The LYWDW seemed to be properly mortified. I have no idea of her politics.
Who knows if that actually happened, but it is certainly plausible. Bush 41 and Barbara were recently seen in United First on a SFO-PEK flight and Bush 43 was spotted on a SFO-PVG flight, so former U.S. Presidents do fly on United.
Let this be a lesson to us all: Never assume--and at least know what the Presidents look like!