We've also been testing this method, and it works succesfully on a new build without any entries in the registry, but on an existing build where multiple users have already logged on and off and multiple entries exist within the Client Side Rendering Print Provider, it still exhibits the same behaiviour as before.
We're still testing and hoping that once a user who exists within this registry area logs on and off, the new registry key will kick in and remove the entries, so it should never happen again for them...
