I was there yesterday. I saw no construction of anything. I didn't even see the sand piles, or at least, they weren't large enough for me to notice.
I just read the thread above, since this was the first I had heard of anything like this. The Venn diagram of Teens and Serenity made me spit out my drink! Too funny. I wouldn't welcome a teen beach so close to Serenity Bay. It was so beautiful and peaceful, I took the last tram back! I guess we will see, but there was nothing yesterday that indicated any kind of construction.