Originally Posted by KARFA

There may be reasons not to extend the flaps after pushback and before taxi. I would generally think that flaps are done prior to taxi, but they don't have to be. In any case, there was a point when they are done, and even if they are missed the flaps are checked at the before takeoff checklist. The checklist is there not as a prompt to do something, but as a check an action or setting has been done. Flaps aren't in the before taxi checklist so I don't think this was a case of them being missed during that checklist.