Good point. I think some sites have already figured this out. I'll find one every now and then that clearly has a giant chunk of text in the center, but the reader view option doesn't activate.
Wonder if there's a flag that disables it or something.
It might be as simple as not adding any semantic markup (an article element for example) for Reader View to use, but you could do all sorts of things with element positioning or pseudo elements to mess it up for non-humans.
