Some of my reviewers have been with me for a long time, and it's really interesting (to me, at least) to see how their reactions change.

You're lucky for that =) I think I can count on one hand the number of people who've stuck with me since the beginning...and considering I think all of them are older than me? I don't have this particular privilege, LOL :P

I bet a lot of people wouldn't even be aware of how a POV shift could affect their reading of a scene like that.

Agreed - its not something you notice until it "feels" wrong, or upsets you and you can't figure out why. But, that's one of the cool things about being a writer, I think :)