My experience:

NRA Instructor, CCW in OH, CO, and FL. Former military, and been a shooter for about 20 years now.

The back story:

I was planning on going to the range with some friends to teach kind of an ad hoc class on different stances, grips, give them exposure and experience with different calibers. Had most of my guns in the locked cases, but I have more guns than cases (though they all fit in my safes in the house.) So, I strapped on onto a OWB holster. I had to run to the local gun shop and get some more targets before heading out to the range. Also had to stop by a grocery store to get some more ice for the cooler. Busy Saturday morning at the grocery so I am actually waiting in line with two bags of ice for about ten minutes (water dripping onto the floor from the melted ice...)

Sure enough...some LEO's come in (yes, my radar is always on for this sort of thing) and talk briefly to the Customer Service rep at the front counter who points in my general area...I think I know what's coming.

I actually make it through the line, having paid for the now half melted ice when the cops come up to me with the Customer service person:

"Sir, there was a call to our office that someone has been causing alarm in this establishment. I noticed you are open carrying and the firearm is in the holster."

"Yes officer, that's correct."

"Sir, have you removed the firearm from its holster during your time in this store?"

"No officer, I haven't."

"Thank you. Ma'am, this man is legally authorized to open carry a firearm in the State of Colorado. It appears he is not brandishing nor holding his firearm in a threatening or menacing manner. We are required to respond to inquiries, so we have responded. There is no threat or danger here. If I may add on a personal note, this persons presence in your store has actually made it safer not less safe because a person who wishes to cause harm would not keep a firearm holstered. If someone like that were to consider entering these premises, the presence of this individual would make them think twice. I would ask that you consider that if you see this individual or any others like him legally carrying a firearm in a holster in your establishment before calling us to investigate. Is there anything else you'd like us to investigate?"

Long pause...cop turns to me and says:

"Thank you sir, you're free to go..."

Note: He never asked me for ID, never asked WHY I was carrying, only if I ever removed it from my holster!

#AWESOME!