Originally Posted by
Thalassa
This is guessing, but it is possible that glasses wreak havoc on facial recognition software. By consistently taking photos without the glasses, automatic recognition becomes a bit easier.
Although that could be a reason, I doubt it.
Security cameras in casinos also check using facial recognition. However, they don't have signs on the doors saying "please remove your glasses and sunglasses upon entering"! If this were so, all cheaters would have to do is wear glasses!