So, is the idea that you don't actually hear that the song is in E (or some other guitar friendly key), but recognize that it's based on open strings on guitar and because of that you just assume it's that key instead of guitar being tuned down?
I can easily say that in the 100's of rock songs that are tuned a half-step down (the entire Guns N Roses catalog for one quick example) and thus lend themselves to keys like G# and D# instead of A and E, that I have almost never encountered a song in G# or D# that were not using half-step down tuning.