I have always felt intimidated going into 'expensive ' jewelery stores'. even though i use to work at my local mall in one. when i first got my DBL EC pink halo ring, i showed it to someone in a different chain jewelery store and they sniffed that they didn't carry J colored stones, because they were not up to their color standard. I tried to explain that mine was a GIA, and was there for better than there IGI graded stones, but they didn't believe me.
on the other hand, I was kind of snobbish about showing the most expensive pieces in our store to say, teenagers for example. when a teenager wanted to look at a 2 ct round for $13000.00, I would ask to hold their drivers liscense first. the reason being, that we were afraid it would be a snatch and run.
when i worked for this particular jewery store, we had a diamond swapped with a cubic zirconia ( it was the 2 ct RB I mentioned above). I never said anything, but I think I was the one that it was swapped on. I had a guy come in and ask to see the most expensive ring in the case, he moved it down below the counter and then back up. he quickly handed it back to me and turned around and walked out. it must have been an inside job, because the ring he swapped had a tag on it, just like the one he stole. I still can't believe that happened to me.