one day at the LGS....
Soe guys brings in a 1911 say he doesn't remember how to disassemble it. So he takes it out of a rug and hands it to the clerk, the clerk asks its not loaded, right. Gun owner "oh no its not", the clerk being smart, pulls the slide back and what do you know a round in the chamber. The he sees the mag in it and its full too.
Thankfully the clerk knew to always check the chamber. He gave a small warning to the customer...
So yes people bring loaded guns into the store...
If in doubt, check it out.
Personally Ive got a habit, pick up a firearm, check it. I am very bad about it. Even if I put it down, and pick it up a few mins later I still check it, its a habit. I check em before the safe, when I take one out of the safe, its checked. I am probably adding to the wear and tear but its a habit. Like not putting your finger on the trigger till your ready to shoot.