Testing Escaped Fragment Search with Webmaster Tools
Apparently "Fetch as Google" does not fetch the same way that Google does. When using "Fetch as Google" the page isn't checked for the meta tag. However, obviously, Google does check the page for the meta tag when crawling.
add a client side "easter egg" keypress that takes the browser's current location and generate the '_escaped_fragment_' form, making sure to escape as needed, and then tell the browser to load that location.
Then to test all you have to do is press your magic key-press and the browser will then redirect to your escaped fragment rendered page.
You can then copy/paste this newly created url into sitemarkup testers, etc.