Originally Posted by
carljanderson
Nope.
For flights May 16 and later, you are going to have to wait to be cleared into W before selecting a W seat. If you're on a Diamond heavy route, you may want to be careful as you could be cleared into a W middle and lose the ability to move back to a preferred seat in Y.
This applies only to "domestic" flights after may 16th. The rules are different for international.