... and reminds me of the occasion that I had been down the back to see friends and when returning to my F seat (in t-shirt and jeans) I was challenged as I made my way through J:

"Are you travelling Business Class?"

"No", I reply. With a menacing waggle of finger I am about to be ushered back down the plane, when I reveal that I am in F (actually).

I smile and say, "can you bring me a Gin & Tonic, please?"

Of course, on certain carriers, I would have been cuffed by the sky marshalls.