In reply to Bradley Allen.

Interesting. I'd never noticed that tiny (+) button in the Yoast plugin until you mentioned it, and had to go looking for it. OK, it pops up an ad for the premium plugin, but only on response to a click on a defined area that doesn't show another purpose, and it goes away as soon as you click the X on the banner.

If the banner came up on its own, or wouldn't go away, that would be a different story, but to me, it might as well not have been there. I'd never seen it before, and I suspect I'll never see it again.