I wanted to quickly fire off a comment, something I almost never do. Instead, and completely unexpectedly, I get a scary modal dialog "Start using your full name on YouTube". Really, that's bad enough as it is. I didn't interact in a way that'd make me expect any kind of dialog (e.g. logging in/out or a major account modification). And there is no easy way to dismiss the dialog without making a decision, no X in a corner, clicking the background does nothing. Also really, really bad. Opening another YouTube window doesn't help, either, you just get another copy of the dialog.
But the reaction to declining the request -- which is the non-default, non-highlighted option -- is just outrageous. Instead of simply going away silently, or maybe telling me where to activate the feature if I change my mind, it tells me it'll show my real name anyway, but just in a preview mode that's only visible to me, if I just click the default, highlighted button. That's not exactly the opposite of what I wanted it to do when I declined their unprovoked offer, but it's pretty damn close. And again, there is no easy way out, you have to chose a reason why you dare refuse them, with none of the options being "I decline to answer" or "Go to hell"; the closest thing being "I'm not sure, I'll decide later", which I chose and which I expect will just mean I'll be assaulted again in the near future.
This is the kind of hostile user experience I expect on cheap travel websites and other scummy parts of the net, but not on a Google property and certainly not on a website I visit a lot.