Is there any chance that they really want you there both days? Like maybe for call backs? And that is why you aren't getting a more specific answer? - because they don't know yet which students will need the second day.
My s is taking professional auditions right now, and those auditions are almost always two days - the first day for everyone, and the second day for call backs. So he flies in the night before the first day (because they often start pretty early in the morning), stays two days in a hotel, and flies out the night (late) of the second day. Usually ends up having a sight-seeing day the second day ...
