Originally Posted by
polonius
No, presumption of innocence is something I get to enjoy while I'm walking down the street, or through an airport terminal, just as much as in a court of law.
You misunderstand the meaning of presumption of innocence. It means that, before you can be convicted of a crime, the state must meet its burden of proof beyond a reasonable doubt. Should it fail to do so, you are not guilty by law.
It has no meaning on the street. Police have no burden of proof, and may investigate based on reasonable suspicion, probable cause, etc.