Privacy is a big issue in modern technology. It is interesting that the two things that are very popular topics among users of technology — and not that popular necessarily among the developers of technology — are privacy preservation and security of environment. These two things are not necessarily compatible — in fact in many situation they are at odds with each other.
In any case, there was an interesting announcement of a technology that will block people from taking your pictures or pictures in your environment. You can read the detailes on this in a News.com article. This technology, obviously yet in research stage at Georgia Institute of Technology, recognizes presence of a camera using retroreflective property of camera lenses and then projects light beams to spoil the pictures like the radar beams used in defense applications.
Whether this technology will become commercial or not — only time will tell. At this stage there is a big gap between the lab prototype and making it practical. But the fact that such technology is getting developed is an interesting demonstration of how technology cycle progresses — a technical solution is required to block use of (or abuse of — depending on your perspective) technology.