Q. What’s the official CMOS stance on double question marks?? I see this a lot in blogs, online magazines, DIY news sites, etc.

A. We don’t have an official stance on double question marks. But to invoke the spirit of CMOS if not the letter, you might keep in mind that any kind of emphasis tends to lose its effectiveness if overdone. This is essentially our stance on exclamation points (see CMOS 6.71), advice that’s equally applicable to doubled question marks.