Originally Posted by
Globaliser
The easiest way to think of it is this: You cannot set an alert for a seat which is currently available, only for seats which are not currently available. Selecting the "Include Blocked seats" option means "Treat blocked seats as already available", so that they are excluded from the seats which you can set for the alert.
The EF wording is confusing, but that is the way that the site seems to work.
Correct, it's explained on the Help popup for creating a Seat Alert:
https://www.expertflyer.com/popup/he...eat-alert.html