I have an AA ticket, but no seat assigned, on a flight that is sold out. Through the AA website, I cannot select a seat, and EF is showing all seats taken. Yesterday morning I set a seat alert for any seat. I randomly checked around 10pm last night, and there was a seat available, so I grabbed it.
The alert is still set in EF. It never fired, and I was never notified.
While I have strongly defended EF, even in light of its slow progress with fixing issue after issue, not reliably notifying for something as simple as a seat alert is pretty poor.