I've "hidden" KB3035583 half a dozen times in the last year (even posting here about how ridiculous this all was and being promptly flamed to ashes). It always comes back eventually.
I'm pretty sure even an update changed from recommended to important will stay hidden too. Though, I wouldn't be surprised to learn that can be overridden.
At least Windows Update makes it obvious when it (Windows 10 installer) returns in some form.
EDIT: clarified last line.
Eventually they'll just start obfuscating what an update does on the website as well, if not lying outright.
There's no grand conspiracy here. Put the tinfoil hat away...
When I'm lied to about updating, and it takes bloody forever normally, it pisses me off. When you start trying to hijack my machine for your purposes "for Win10", you can collectively fuck off.
I'll set on my Windows Machine (yes singular, all others are Linux variants) for No-update Windows 7. And I'll also switch everyone I know to no-update as well.
I don't know which, and don't really care. Either way, there's a case to be made for disabling updates entirely.
Basically, the way they're going, it's only a matter of time before Win 7 & 8 basically don't work anymore.