I think I'm inclined to agree with some of this.
After a period of intense speculation, and the dodgy photo, Kate pops up looking years younger, and - many people believe - quite different.
I think anyone saying "erm..hang on a sec, isn't this a bit odd?" isn't necessarily a tinfoiled-headed nutter. They're possibly just an average person finding the situation a bit... unusual.
I mean, thank goodness for grainy mobile phone footage, because otherwise, it would just be one single person recognising the future king and queen in a farm shop during a period of heightened speculation, while no one else batted an eyelid or reached for a camera.