Recently a German Sikh leader was forcefully asked to take off his turban. This was again in the name of security. The incidence took place at the Milan airport in Italy. The victim has complained to the Akaltakht in Amritsar. I don't think that this is something wrong and people are totally free to follow and accept their religious affair anytime anywhere. But yes, for the security purpose if he the person is asked to take off the turban or anything then there should be no harm and people should cooperate with the security people.