Do sessions work with multiple web dynos on Heroku?

If you are running a Rails 3 app with multiple web dynos on Heroku,

1. Every time you hit the app, do you typically connect with a different web dyno?
2. Can sessions work across different web dynos?
3. Does it work for different Rails session stores (ActionDispatch::Session::CookieStore, ActiveRecord::SessionStore, and ActionDispatch::Session::CacheStore)