I believe this is a bug with the software, and therefore might not be easy to reproduce. If it was common and easy to reproduce, I would guess that Apple would have patched it up by now. However, it may be related to a similar problem that was prevalent in earlier OSs...
There was originally a bigger problem in earlier versions of the OS when there was a lower limit to the amount of apps you could install. Once you installed too many, they would disappear. Since then, Apple added folders and more home screens making it much harder to reach the limit now.
On one of the earlier OSs (I believe it was iOS 2.something), you could repeat this by moving apps to the hidden 10th screen. Basically, you would fill up the 9th screen (the last one available at the time), and then begin pushing apps to the 10th screen. Once you were done editing, they would no longer be available.
I believe this is a bug with the software, and therefore might not be easy to reproduce.