Wikipedia NOR Britannica are citable sources. EVER. Nor any other encyclopedia. They may be citable in grade school, but not once you get to university.
It’s always been that way, and it affects all encyclopedias and Wikipedia equally. It does not matter at all if Britannica verified everything.
Encyclopedias are not primary sources. They never have, and never will, be citable.
The whole point of an encyclopedia is to gain knowledge in a general sense. If you know little about a subject, an encyclopedia works great because it gives you background information to begin your hunt. Even better, it’s got a references section that helps direct you to the primary sources to which you can look up the information and get a deeper understanding. And THOSE sources are citable.
The same goes for Wikipedia. Ignoring errors and edit wars, Wikipedia will never be a primary source (and they aim not to be, either – no original research). Wikipedia’s got an advantage over Britannica in that it has a lot of pop-culture articles and thus is more useful.
The quickest way to get laughed out of higher education is to cite an encyclopedia. Britannica, Encarta, Wikipedia, it doesn’t matter. It doesn’t even matter who’s an authority figure. When you’re doing research, they’re excellent starting points because they cover the general background and have the much-needed reference section of every article to launch your research.