I have Romancing the Stone on Blu-ray. I love the film, watched it when I was a kid on TV and had a tape of it recorded that I used to see sometimes. I've watched it once or twice since then. So, I've probably seen the film about ten times in my life, would consider myself a fan, and bought it when I saw the BD on sale. But if they added CG rocks to the background of a shot or two, or changed a minor line of dialogue, I doubt I would notice. And if the colour looked basically as I remember it, then I wouldn't think anything was amiss, any differences I would pin down to the BD/remastering making it truer to the original colours.

I mean, complain as we do, Hoth has been blue since the 1995 THX release that everyone bought, the blockade runner is still white-ish, and the Death Star has always been grey-bluish, so as far as most people are concerned the films look about the same as they always have.

So, for Star Wars fanatics, yeah they should be more attentive, and probably are at least vaguely aware of all these things. But the more casual fans, aka just "fans" where more regular films like Romancing the Stione are concerned, won't notice these things, and it's not because they are stupid, they just don't memorize every movie they watch. There are a lot of videos I've owned like Rocky where if I didn't read on the internet that there are visual differences from previous ones I would never have known.