My loyalty to AA is significantly based on the ability to get "tolerable" seat assignments months in advance of a flight, and to have those seats still in my posession on flight date. As mentioned above, DL does not honor this, and I do EVERYTHING IN MY POWER to avoid DL solely for this very reason. (Since I am top-tier on Delta, it is obvious that I can't avoid Delta all together. But I could easily have 150,000 miles on DL if it weren't for the disappearing seat assignment dilema).

So, while I understand my "legal" right does not vest title to my exit row reclining aisle seat, may I assure you, if I had a seat I liked at booking, but it disappeared at flight time, and this happened randomly and frequently, I would avoid that airline like the plague.