Not sure about police officers, but the other professions you named have to complete graduate or post-graduate studies in their field, pass a formal examination, maybe publish a few peer-reviewed papers while architects build a portfolio - this is usually proof enough of their strengths.
Actually, this works in IT as well: if Donald Knuth, Yann LeCun or Zvi Gallil ever decide (however unlikely) to apply to a web shop, they'll probably get waved through on the strength of their credentials. For the self-taught J. Random Hacker, who can't show any of his old code because it's under NDA, there's the interview pipeline.
Actually, this works in IT as well: if Donald Knuth, Yann LeCun or Zvi Gallil ever decide (however unlikely) to apply to a web shop, they'll probably get waved through on the strength of their credentials. For the self-taught J. Random Hacker, who can't show any of his old code because it's under NDA, there's the interview pipeline.