To answer your questions: Since wearing the niqab is not obligatory according to the view of reliable scholars, then removing it at times of necessity is also permitted.
For example at a Air port, or when you doubt the identity of a woman,etc.In SL during the war I've had to remove my niqab for identification purposes.Since the security situation was so vital all us ladies in the veil had to corporate. In fact even here in Qatar, due to the absence of a lady in charge, my sister had to show her face to a male employee at the Visa office when applying for her RP. This is all ok as its more obligatory to follow the law than to wear a niqab which though highly rewarding is still not a must.
To answer your questions: Since wearing the niqab is not obligatory according to the view of reliable scholars, then removing it at times of necessity is also permitted.
For example at a Air port, or when you doubt the identity of a woman,etc.In SL during the war I've had to remove my niqab for identification purposes.Since the security situation was so vital all us ladies in the veil had to corporate. In fact even here in Qatar, due to the absence of a lady in charge, my sister had to show her face to a male employee at the Visa office when applying for her RP. This is all ok as its more obligatory to follow the law than to wear a niqab which though highly rewarding is still not a must.