It does happen a lot however it's usually from celebrities who can afford to have a separation of a personal and private life. ie people who's career might be i

It does happen a lot however it's usually from celebrities who can afford to have a separation of a personal and private life. ie people who's career might be in the public eye but they're career isn't solely based on the fact they're famous (eg sports personalities, actors, musicians, businessmen of household brands). Where as celebrities who's day job is being a celebrity (eg appearing on "reality" or celebrity game shows) need the publicity because their fame is their product. So for all but the most extreme cases, suing paparazzi would be a bit of a footgun move considering they're often dependant on that free advertising to remain in the public conciousness.