I'm sure the op was not devious, but personally I certainly feel sorry for the poor passenger who felt obliged to accept to surrender an UD seat in favour of a less coveted lower deck one. Quite frankly, if it were me (and we often travel on separate PNR so it could have been), I would have never accepted someone being asked by the CSD to make that move on my behalf as it would have made me feel selfish.

And I agree with others it always is the people wanting the change getting the better seats. Had it twice this month when in row 1, one of the two times with someone who had pushed everyone around at boarding who had settled in 1F next to his wife and said that as he was travelling together with his wife could I take his seat 4F.

I think it is rude to pretend not to notice that not all seats are equal, and I think the CSD in the Op's case did a very poor job not politely telling the op that since most people prefer the upper deck he'd/she'd ask the person downstairs first. I hope that the person pressured into moving complained because it seems to me that a wake up call on seat change etiquette and what is, quite frankly, a polite or rude way to conceive them is well overdue.

And as I know some people will say 'he could have said no if he didn't want to', it is quite frankly equivalent for choosing to punish people who happen not to be pigs and typically want to comply with crew request rather than be selfish and cold hearted. It is both hypocritical and unfair.