Not in Texas. As I understand it, you haven’t broken the law if that’s how the sign is worded.
Texas statutes define the exact wording, letter size, etc. required for such a sign to have legal force. The exact PE code is here. Again, as I understand it (from an attorney at my CHL course), it must have the following wording: “Pursuant to Section 30.06, Penal Code (trespass by holder of license to carry a concealed handgun), a person licensed under Subchapter H, Chapter 411, Government Code (concealed handgun law), may not enter this property with a concealed handgun.” These are called “30.06 signs” around here.
Also, Texas had a problem with gun-grabbers posting 30.06 signs where they’re not allowed. The legislature dealt with this by passing SB 273, which deals harshly with the “Wrongful Exclusion of Concealed License Holders” (from the bill’s title). Illegally excluding handguns can now cost a minimum of $1,000, and a minimum of $10,000 for a second violation. Each day the sign is up is considered a separate violation. Limiting gun owner’s rights can get pretty expensive in the Lone Star state. 
Again… IANAL, just responding with what I’ve read and was taught.