Originally Posted by
corporate-wage-slave
It prevents you moving to other seats. So if you hold back on that (and emailing, faxing etc) then you can watch as other seats become available and move accordingly. If you like the seats you have got then naturally you should go ahead and get the boarding passes.
On a recent flight I got the exit row seat I wanted (16F) from booking until I printed the boarding pass.
After that, they swapped from an A320neo to a A321 where I wouldn't even have had a window in that seat.
Finally I was able to be moved to 23E at the airport, still no window but way more legroom and 23D even stayed free.
So, maybe don't even print when you checked in on the seat you are happy with?