Macbook loose screen

[m830mr]

I got my macbook on 8/28. Right off the bat I noticed that with the lid closed there is some very slight wobbleness when you apply force to one side of the screen or the other. I brought it to the mac store and they said it's normal. Not only that but we checked all the macbooks there on display and they all did the same thing. Now I don't know if this really is normal but it makes the macbook feel really cheap when I'm carrying it around. Has anyone else noticed this about the macbook? I'm thinking of just taking it to the apple store and seeing if they can do something about it under warrenty.