Don't forget that moving out of EC and you are moving out of the
complimentary liquor drinks zone (intl flight).
As noted previously beware of standbys be they revenue or non.
At the gate eyeball the area and ask the GA how many standbys
are standing by for an answer to your move or not move question.

Non-revs are accommodated by class and seniority in the front cabin
until full and then the EC seats till full and then coach starting from
the front to the back - so I have been told. So take that into account.

And why should you move when possibly the middle seat EC pax
will be the one moving to somewhere else for more room.
By moving you give the edge to that middle seat pax - WHY ?

Don't play the trump card until the seating situation is to your liking!