Technically speaking, it it not necessary to play the high E string when playing an A major shape barre chord. This is because you are playing the same note on the D string. For instance, when playing a B major, the F# note appears on both the 4th fret of the D and the second fret of the high E. So not playing it (I'm assuming it's muted) still gives you a B major chord.

I play the A shape barre, as I think most do, by covering the D, G, and B strings all with my middle finger. That means to play the high E you have to arch that finger up, kind of back-bend it if you will, so that it completely clears the E string in order to get that note right, Not everybody can do that. I can when I try, but it's not consistent, but if I'm not completely clearing the E with that finger than I am touching it a little and thus muting it. That to me is acceptable. The A major shape barre is hard enough as it is; I figure no reason to be nit-picky.

Mike