I can’t. That’s just a copy-paste from the docs. I don’t really understand. I took a look at update.qubes-vm but I can’t see any current “built-in security measures”. It might have been the case previously? So, even if there are currently no security measures, it might be the case in the future?
Anyway, I think it’s better to stick to the official API. Maybe this warning is too dramatic in this context, but I wasn’t convinced by providing this script as a community guide and I was looking for a quick way to tell users about this, thus the copy-paste.