It's depending on when the flights arrive. There need to be three days of formal activities. For instance, we arrived on my flight at 10 o'clock on the first day. So we actually had an afternoon and an evening. The fifth day was a write-off because we went to the airport at about 4:30 in the morning. There are three days that are guaranteed to be set aside that folks can use.
On April 17th, 2008. See this statement in context.