I was told by a friend that the Sprint store in Fenton is posted "No Weapons". I have not seen it first hand because I deal with Verizon.
Babies-R-Us is posted "No Firearms"
Hometown Computers in Fenton has a sign encouraging legal carry. The sign basically asks you not to unholster unless needed for defense in which case it asks that you hit your target. I am paraphrasing because I don't know the exact wording but I will support the business because of this.