I think one of the reasons Strats have that gorgeous neck pickup tone - I dig it, too, even though I stopped trying them - is that their lack of bottom end reduces the lower midrange mud and delivers a nice, clear signal to the amp.
I’ve never tried taking the back cover off a Strat to see if I could hear a difference, so the folks who can hear it, bravo! However, it makes sense that there’d be a resonance in a hollow cavity that’d be picked up.
