I found that multiday sessions display best in the calendar and in the emails if I add multiple dates to each session.
When I do this however, each date in the session (Monday - Friday for example in 5 day course) shows up as a separate event in the Upcoming Events block. This means that the future courses are way down the upcoming events list and it's as confucing as hell to users.
Shouldn't one session, even if it has multiple dates equal one event? I know we all use this module differently but this does not make sense to me.