As a photographer myself, i think this is a bit over the top to say the least, its a poster from London Met.
There seems to be increasing occurences of people being stopped for taking photographs by security and police.
I think its mental state, when people can access maps, and google photographic maps of areas quite freely, yet amatuer photographers are being pulled over if they are deemed suspicious.
theres more of a story here
http://news.bbc.co.uk/1/hi/magazine/7351252.stm