From what I see, it schedules the upgrade, and you have to opt out by going into some other settings to cancel.
It's not that the "X" activates the upgrade - at that point, it's too late.
Still, it's very shady not to give users an obvious choice on the popup, let alone not making it an "opt in" choice.
All of my machines are running Windows 10... shrugs... at this point, all the bitching is basically all about the point of the matter. Win 10 runs fine on the machines I've installed it on (several laptops, 9 or 10 desktops, some 10+ years old). Unless you have some particularly specific niche software or hardware (that can't run in Win7, therefore, not in Win10, since the drivers are mostly the same), people really shouldn't have too many complaints.
I'd be more concerned if Microsoft was pushing people to Win8 and the crappy fail that was the Metro Start Screen. Win10 dialed it back and makes more sense in the case of a desktop/mobile hybrid OS. Still, the exec who is pushing this sort of tactic needs to be fired ASAP.
I upgrade 2 out of 3 of our coputers to 10. But the last one is our HTPC with Windows 8 + Media Center on it. Media Center doesn't exist on windows 10 and never will so the last thing I want on that computer is the upgrade. Having to go through all this non-sense to avoid the "upgrade" is unacceptable. We're not dealing with a shady company from Ukraine or India here, this is Microsoft for crying out loud! This is insane. I am totally p*ssed at M$ right now.