Originally Posted by
sethb
If they didn't expect the flight to be full, picking aisle/window has the best chance of getting all three seats, because someone else is less likely to take the middle than the window.
Oh I'm well aware of that. I was just responding to the fact that some FTers can't seem to fathom that not everyone else has the same travel preferences they do; i.e. an FTer can't comprehend someone else's preference order of
1) Window/Aisle with open middle (hence selection at booking for reason you stated)
2) Aisle/Middle with the would-be middle seat holder taking the window
3) Aisle/Window with occupied middle seat
4) Lastly, Window/Middle with would-be middle seat holder taking the aisle seat. But since OP stated option #4 is a no-go, the pecking order will stop at #3, which was the status quo to begin with.