I recently wanted to delete the latest backup version of a job, and decided to d oit via web UI. This was the first time I was doing it, so it took a little adjusting to the logic of the web page where I select the different sections of the command line. At end, I decided to add --dry-run, but it had no effect, which was baffling. After some snooping around, I learned that it takes a value and that the default value is false. At the time when I was picking up the option, i was already ready to run the command, so I didn’t even realize that the selected option had not appeared anywhere on the page. If I had scrolled back up and selected to see the textual version, I would have noticed the wrong value, but my decision to use dry-run was a last-second thing.
In the end, nothing bad happened. I did want to remove that version, and it worked fine. But the experience with --dry-run was scary, to put it mildly.