POST requests

[andyhd]

Currently, only link tags are automatically decorated to add the UID as a URL parameter. What about form submissions or other means of sending the browser to a page on another origin?

[andyhd]

The client Javascript could automatically decorate cross-origin form URLs too. But is there a potential problem here? Extra URL parameters might cause problems in form handlers, and an accepted best practice is to perform an HTTP redirect after receiving a POST request, so the redirect URL would need to include the UID. This would have to be done server-side.