In the case where, as a consequence of a natural (or man-made) disaster, the network infrastructure is not operational, video/audio testimony of the humanitarian situation can be crowdstreamed through a chain of mobiles until it reaches a device with Internet access.
It is unlikely that an application designed to support relief in humanitarian emergencies caused by natural disasters would be subject to attacks, though such attacks may occur if the disaster is man-made, e.g. war. It may also be advisable to develop countermeasures against possible malevolent use of the application in situations for which it was not conceived.
To respect the privacy of any person who may appear in a video stream transmitted via the application, human faces should be blurred before such a stream is published. This could be of particular importance in the case of victims of natural disasters whose friends and family may not wish to discover their predicament unexpectedly via such publication. However, arguably, in the scenarios envisaged for the