That's really not that interesting. I work as a research scientist at a face recognition company. If you want, you can detect faces at any angle, but sometimes for speed you will only check upright faces.

it might not be interesting to you as a researcher, but to me as a participant in in a world increasingly filled with face recognition products it's worth knowing that different products will have different capabilities based on their "speed" requirements.

I am not a researcher, but I would suggest that perhaps you would find that in the case where a crowd was being parsed in realtime (looking out for somebody so we can catch them before they leave the station for example), the "speed" dial would be turned up as high as necessary, but that the video stream would be stored and the data set reprocessed at a later time with it at a better setting (so you can still say "yes she was here at x time, though we missed her")

in other words, the bandwidth of the image recognition product is not the same as the bandwidth of the video storage.

yes, highlighting what is possible is always needs to be taken into account. But again, what is possible is not the same as what happens in reality. Just because we can't rule something out, does not make it certain either.

> the "speed" dial would be turned up as high as necessary

It's possible, and probable given the situation (i.e. government, terror acts), but are there situations where this wouldn't happen in a different circumstance? Would mall security, or a marketing company operating an advertising product, have the ability, authorization, know-how, or financial incentive to do so if this wasn't a life/death situation?

Not every application of facial recognition technology will be targeted to terror suspects/bombings.