The login screen is much simpler and controlled than the full session. Its much more likely to work than a full session where you can run any application and do

The login screen is much simpler and controlled than the full session. Its much more likely to work than a full session where you can run any application and do anything. Sounds like a pretty good starting point, much better than introducing it for the whole session. I'm sure there will be a way to disable it to work around issues, but this way we get broad testing while not risking the stability of people actually trying to get their real work done (after logging in).