Both the LAE and Captain seemed to take a look, whether it didn't register, who knows?
Quite possibly that is the case. We (airline pilots) have seen the video of the basketball passing competition between two teams. We were all surprised the first time we saw it that there was a person in a gorilla suit walk through the middle of the competition. Its called functional blindness. Basically if you are not looking for a specific object then it won't register that it is in fact in your field of view. Its why bike riders have cars do a u-turn in front of them. What is harder to fathom is the lack of airspeed not being noticed on the PFD's. The pilots should be expecting to see that during the take-off. Tracking technology on the pitot covers is not a bad idea but should there be some sort of alarm similar to the take-off warning config if the IAS is not increasing? Ideally, trained pilots should pick up such a basic fault but I use the analogy of the professional soldier and the conscript. The conscript has basic training but is not interested in improving their skills beyond what is necessary. The professional soldier wants to keep improving so they can be the best they can possibly be. I think worldwide that there are too many pilots who are in the conscript category. The recent incident in Dubai is another example. Four pilots who did not know how to comprehend a situation that was different to the hundreds of departures they had sat through and watched previously.