Interesting. People on BART ten years ago would read over my shoulder or borrow a section. Or talk to me about the book I'm reading. I like holding books up at eye level rather than looking down at them in my lap just for neck strain. That makes the cover more visible for sure, but I don't think it's a significant factor in the interrupting. Just in the noticing.
How strange. I wonder if this is a SF thing? Or a recent development (10 years ago counts as "recent" to me)?
In my part of the country, anyway, that sort of behavior has always been considered extremely rude (or at least over my entire lifetime). I wouldn't even consider doing it, and the few times it happened to me, it was exceedingly irritating.
Fascinating. I've only been in the Bay Area for 10 years or so, but I recall this would very rarely happen to me on East Midlands trains before that. Certainly never on the Tube. But I've also changed in that time and it is possible some aspect of my demeanour invites this. All for the best, I suppose, that people treat us both as we wish to be treated.
I never minded.