Programs: UA 1.25K, HH Gold, Club Carlson Gold, Global Entry Platinum
Haven't had it happen to me but I think I caused it once.
Called up to move my wife into E+ and get her seated next to me (separate PNRs) and the CSR said something to the effect of "wait just a sec, I have to move some folks around" before telling me that my wife and I were now seated together in the row I had requested.
Even more common if you have booked a code share flying UA metal. I noticed my E+ moved to E-. When I queried the 1K desk, it showed that the new seat was requested by LH. My guess is that becuase I made my seat reservations direct with UA, LH was clueless and since they don't assign seats til later in the process, LH went in and assigned a seat arbitrarily based on what might have been available at the 11th hour. This may have no bearing on the OP's situation, but it happens....
Programs: UA 1K, HH Diamond, Marriott Platinum, Avis 1st
Yep - as a lowly 2P my E+ aisle seat was re-assigned with no warning to a 1K who thought she was too important to sit in the middle seat in the row despite being on standby. I knew nothing about it until the gate agent called me to the podium five minutes before boarding and tore my boarding pass up and issued me one for 6E instead of 6D. I heard the woman on her cell phone after boarding and put two and two together.
Programs: SPG Gold, HH Gold, AA Gold, UA3P, DL proletariat, US nothingness, proud Costco Executive member
Thanks to this thred, just checked my ewr-den-lax-lih itin, and found just that, that my E+ seats gone on first three legs, strangely, even on UA69 which was original flight. Seems they've rerouted us via ORD instead of DEN, because of an hour earlier departure from DEN caused the ewr xfer to DEN too short. How hard is it to retrieve the E+ seats at night? Are the call centers any better? Any tricks for getting HNL online?
Also, don't want stuck in the no-window E+ -- suggestions?