Costco is the one place I can list off the top of my head where a legally concealed weapon initiated a call from an employee to the police because they spotted his CCW. When the police confronted the person who was LEGALLY carrying their CCW in the parking lot of Costco, they ended up wrongfully shooting him to death.
http://pjmedia.com/blog/gunned-down-in-vegas-what-really-happened-to-erik-scott/
Mr. Scott did several things wrong that day, but Costco appears to be pretty dang anti-carry...or at least the responding police were.
"A Costco employee saw the holstered sidearm and told Scott he was not allowed to have the weapon in the store. Scott replied that he had a permit and the right to carry his weapon. He then went back to shopping. The employee called over a manager, who informed a 20-something security guard, who made a 911 call to police."
"As the police began to form a massive perimeter outside, Costco managers began evacuating the entire store without apparently explaining why to anyone. As Scott and his girlfriend exited the store he was identified to police officers, who were waiting with guns drawn outside the front door."
"Erik turned to find three officers facing him, guns drawn, and all three shouting different commands: “Get on the ground!” “Drop your weapon!” “Keep your hands up!” Erik held his hands up, spoke calmly, told them he DID have a concealed firearm and a legal CCW and was an ex-Army officer. His girlfriend was screaming about Erik being a West Point grad, former Army officer, etc. Erik leaned to his left, hands still up, to expose the pistol, and repeated, “I am disarming; I am disarming.” Witnesses say he started to lower his right hand, palm OUT, perhaps intending to remove holster and gun together — but never got the hand below his shoulder, when one of the cops (believed to be William Mosher, who had committed a fatal shooting in 2006) shot Erik in the chest with a .45-caliber semi-automatic weapon. Erik dropped to his knees, clearly in shock, his face a picture of disbelief. He was shot a second time and collapsed. The rest is ugly. The three officers unloaded again, firing a total of seven hollow-point rounds. At least four, possibly five, hit Erik in the back, after he was on the ground and dying."