Google addresses redirects from
_escaped_fragment URLs in their FAQ:
Can I use redirects to point the crawler at my static content?
Redirects are okay to use, as long as they eventually get you to a page that's equivalent to what the user would see on the #! version of the page. This may be more convenient for some webmasters than serving up the content directly. If you choose this approach, please keep the following in mind:
- Compared to serving the content directly, using redirects will result in extra traffic because the crawler has to follow redirects to get the content. This will result in a somewhat higher number of fetches/second in crawl activity.
- Note that if you use a permanent (301) redirect, the url shown in our search results will typically be the target of the redirect, whereas if a temporary (302) redirect is used, we'll typically show the #! url in search results.
- Depending on how your site is set up, showing #! may produce a better user experience, because the user will be taken straight into the AJAX experience from the Google search results page. Clicking on a static page will take them to the static content, and they may experience avoidable extra page load time if the site later wants to switch them to the AJAX experience.
Given that redirects are fine as long as they get to the same content that the user would see, I don't see any reason that cross-site redirects wouldn't be fine as long as they get to the correct content.