I too was looking for the trick in the question.
First, it used DATE instead of DATETIME which gives you an error if you're using Server 2005. The Insert command would also not work on 2005.
Then, the between was comparing string values. I had to guess that it would automatically convert those to date.
To make things worse, it was using the date in yyyy/mm/dd format (or was it?). All those dates would still be valid in yyyy/dd/mm format too. What date collation was set on the server? Who knows.
Anyway, I answered correctly but I have to admit it was just a guess this time.