Covered to prevent the journalists & bloggers from reporting on new products in development. If you think the covers were only there to prevent photographs, you are mistaken. Do you really think Apple has the mindset of 'you can look at our new iPod touch, so long as you don't take a photo of it'?Millions of dollars and all they can come up with for storage are plastic bins you can buy at your local office/home store? Really?
I also must say, these aren't "leaked" photos. I am not sure the intent of the photos but clearly it was planned for someone to take the photos. Everything is covered in anticipation.
OP - do you work there? That would explain it. Somewhat.