The case of the mistaken identity of Neda Soltani in 2009 during the Iranian protests is worth reading:

http://www.bbc.co.uk/news/magazine-20267989

> The whole thing happened in a matter of 12 days. In less than two weeks I had gone from being a professor of English literature, leading a very normal life, to a person who had to flee her homeland.

All because somebody mistook her facebook profile for someone else's