That's the same as it was in the lab I worked at. "flop" and never "flip".
Maybe it's a Pacific Northwest thing...
One lab I worked for made reduced dupes for ganged separation. Now that we have scanners, almost nobody remembers how expensive separations were. Making them was a skill that required a lot of training and experience in individuals who wore white lab coats. Duplicate transparencies were expensive too, if you needed good ones. Even so, they cost far less than individual separations, especially when you considered the additional stripping, registration, etc. that had to be done individually in quadruplicate.
Since emulsion-up is normal when you make dupes, the "flop" thing could get really confusing if you weren't very careful. I think I must have seen the word "flop" several thousand times.
"Flop" in a photojournalistic context:
The orientation of the image, right reading or mirrored, may or may not be important to the story. If it isn't, art direction will frequently take the liberty to flop an image if graphic considerations require. Why not? It's done all the time.
In one instance in my experience, an image of a train pulling into the station at night was flopped to keep the train from driving off the page. Nobody ever noticed, because the illuminated numbers on the locomotive were halated beyond recognition. It could have been heading north, or it could have been heading south. Maybe someone intimately familiar with the Yakima, WA depot, after studying it microscopically, could have found some clue that would reveal a possibility of "deception" but who'd waste time on that? The value of the image to the story would remain intact, regardless, while the presentation of the image in the layout as taken would have sent the reader hurrying on to the next page, missing the story entirely.