Sorry - But, your wife has no beef now, but did have one onboard. She chose not to follow your very sound advice.

The time to raise safety & security, let alone comfort issues, is on the spot. If she felt uncomfortable doing so in front of the COS, she could have headed to the galley (yes, a PITA to climb over someone) and insisted.

I've done it twice. Once the other person was moved to a location with an empty middle seat (I think) and the other, I was moved to F outside the UG process.

Sure DL might have caught this before boarding, but that doesn't mean that people can't take action themselves when they are put in unsafe situations.

The title of the thread ought to be changed to "what should I do when..."