title: Google distancematrix API without a key
body: <p>I have a python script to calculate driving distance between two points.  Here's  my API call.  I did not use any API Key.</p>
  
  <pre><code>urlGoogle = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=" + origZip + "&amp;destinations=" + destZip + "&amp;mode=driving&amp;units=imperial&amp;language=en-EN"
  </code></pre>
  
  <p>Once while testing with lots of data I got an error for exceeding the limit.  My question is how does Google track/monitor my usage without a key.</p>