yes, i don't think anyone can easily forget about those disturbing video footages anytime soon. creepy~
i'm not undermining the jobs the security are doing, and i'm certainly grateful for that. but seems to me though, more like an exercise in doing something 'for show of force' rather than any concrete threat prevention :dunno: video and photos can be taken stealthily, from afar, or 'agents' can be put in place for real-time surveillance and recon.
funny thing i noticed, if you are shooting handheld, they are less likely to approach you, than say, on tripods or with extra equip. i don't see the security actively stopping tourists from taking photographs that day. but have personally heard stories of people getting stopped when they were shooting on tripods, presumably for more 'professional' photos.