Well, what about when your government does something you don't like and you protest about it? Then they aren't looking for you. They're looking for anyone near that protest at that time. Then they come and detain you against your civil liberties. After all, they had no problem spying on you all that time; why should they be concerned about whether you've actually done anything illegal or not.

This isn't science fiction. This happened in the US under Bush.

"Als sie mich holten, gab es keinen mehr, der protestieren konnte."