OK thanks guys! UK view :
So airport well within their rights to ask you to stop, refusal can have you denied boarding or escorted off premises. No right to have data wiped in normal circumstances.
btw I see people taking photos every day when I have to board via steps. Instagram is full of them and airlines love the
PR and social media footprint this brings. Thus far no one has managed to make an aerplane explode by using an SLR within 3m of a fuel vent.