There’s a reason they are called “concealed weapons”.
Here in the state of Washington there are a few places where you can’t carry a gun (schools, courthouses, and bars). Maybe some/all sports arenas? (It has been so long now!)
Businesses can put up a “Guns Prohibited” sign but if they do somehow see that you have a gun the most they can do is ask you to leave. If you don’t leave, then they can call the police on you for trespassing.
Not to say that somebody might not freak out if they see the gun, and call 9-1-1 and yell “the guy has a gun come quick!!” and you get killed by SWAT. (Like happened at the Las Vegas Costco years ago.)
And it's just another charge to tack onto anyone who has to defend himself.