The sneakiest thing just happened to me on that Washington Post site. There was an overlay ad, no big deal, with an X to close it in the upper right of the screen. I moved my mouse up there to click the X and the site shifted slightly so what I actually clicked was "Subscribe"!
Different A/B test group? Or could just be that the site is hot garbage, every time I reload the banner/overlay ad and top bar behave slightly differently, I can see how that could happen but I couldn't get it to do quite what you've seen after like 20 reloads.