I bought my 2008 GT last year, and I got both smart keys with it. I like very much having the feature of the lil button on the door handle that unlocks the doors. However, 10% of the time that booger doesn't work.
Likewise, when starting the car with the key in my pocket, 30% of the time I get the red key reject on the dash. I have to pull that sucker out of my pocket, hold it up against the dash, then I get the green key indicator and I can start it.

As if that wasn't enough, neither remote will pop the trunk (I have to use the key or the button under the dash).
So I ask you, why is my smart key so friggin stupid?!?

 

I never had problem with mine but check and see if your need new battery, also don't put smart key in the same pocket as cell phone, interference will cause the car not recognizing the key.

if you still have warranty, go back to the dealership to have them check it out.