For God's sake! Photographers, plural, means that the apostrophe comes after the word photographer, in other words "photographers' " and.....what am I saying? Just to put a counter-point (this is going to make me really popular) but to the best of my knowledge there is an act of "Hostile reconnaisance" at a potential terrorist site, on average, once a day in the UK. As an example, last year at a UK airport a member of the public reported a young asian male as acting suspicously. When the cops turned up to speak to him he was see filming the structure of parts of the terminal building on his phone. All the parts of the building on the phone were potential weak spots where an explosive device would cause the most damage. The young man stated that he was an architecture student studying for a degree in Pakistan. He was not known here and when asked, deleted the film from his phone. Student? Terrorist? Facillitator?
Some parts of the old Sec 44 were ridiculous, such as photographing the Houses of Parliament from the embankment or Buckingham Palace from the Mall, but nowadays with e-mail a recon photo that would have taken 24 hours to process and another couple of days to get to the planners can now be there in a minute or less.
Ironically, instead of treating photographers as potential enemies, it might have been a better idea if the Home Office and police forces had thought about how observant many keen photographers are (almost by definition) and encouraged "them" to use those observational powers to spot the difference; the difference between a snapper and someone who's taking photos that seem perhaps a little odd.