The mug shows length of stay as a purchase option, so if you are there for 5days/4 nights I would assume you get 5 days of mug right? Not 4 nites worth of dining like the dining plan does.
The max is 14 days so I wonder if it's really 5 days or if it means 14 days once you pass 3 days. I will find out for sure at the end of November as I will be staying at Poly for 6 nights with a package and switching to AoA for 2 nights without a package. It would be nice to at least keep the mug, but we will see.