It's about money, about license costs and such things. The question is: how to control that? Do all visitors have to hand over their smartphones?
TechCrunch :: Don’t copy that pole vault! According to the London 2012 Olympic “conditions for ticket holders,” you are not allowed to take pictures or video of the events nor are you allowed to “exploit” any video on social networks.
Images, video and sound recordings of the Games taken by a Ticket Holder cannot be used for any purpose other than for private and domestic purposes ...
Continue to read here John Biggs, techcrunch.com