title: REST standard for GET on a resource that doesn't exist
body: <p>The resource /user/12345 doesn't exist. Lets say the consumer is trying different ids randomly. There is no authorization. Any user can view any user. In a broader sense, my question is "What should you return if you do a GET on a resource that doesn't exist?"</p>
  
  <p>Should I return an empty user for an id that doesn't exist or should I return an error message with proper status code?</p>
  
  <p>What is the typical/usual/recommended practice?</p>