Have a mr, MSY-iah-ewr-hkg-SIN, booked on .bomb, and got seat assignments for all legs except hkg-SIN. Tried 4 days in a row on .bomb to get a seat assignment in one of the empty seats in what looks like the e+ cabin but no luck. Called this a.m. - got thru in a minute or two - called the old 1K phone line, which is also the same number on new 1K cards from CO - was told that the forward portion of economy cabin was blocked for some unknown reason. Tried again a few minutes ago - most helpful agent spent almost an hour, talked to supervisor, but no seat assignment. (it's a 3,300 mile flight, a window seat, forward of the wing, would be nice but they're going away fast. Have seen blocked sections, and they typically go across a cabin, not random selections of aisle & window seats, leaving middles, so it seems to be more than blocked out for tour groups). I believe the phone agent was trying. Was advised to try for a seat on check in at MSY. Puzzling - on this mr, all legs but this one allowed seat selection, in E+, but not this leg. Worse things have happened (well, they are already on this flight, believe CO is charging for booze in coach, even for transpacs or flights w/in Asia) but stuff like this partly explains why CO has high call volumes.