[mikeash]

I'm not addressing any sources of acceleration. I'm only looking at the final acceleration vector. If the magnitude of that vector is 1 gee, then there are only two possibilities. One is that it perfectly opposes gravity, resulting in zero net acceleration. The other is that it doesn't perfectly oppose gravity, resulting in downward vertical acceleration. It is not possible for a 1 gee acceleration vector to result in upward vertical acceleration, regardless of what causes the acceleration.