And yikes at your experience Ingesu. Scary! Which kinda reminds me of how this dude gate crashed a ladies only event once wearing niqaab. My sister's friend had to make the ghastly discovery.
That said I must tell ya that before we board any planes, we are made to uncover our faces at the airport offices to prove our identity. Even here in Doha we have to show our faces to the visa officials. Obviously women with niqab HAVE to be checked cos the truth is yes..anyone can be under em! And we niqab adorning Muslim ladies do understand this and hence don't protest against such measures.