Well, as long as you guys are communicating, its all good.
I would think that barriers would give off some vague sort of idea of what they do. A normal human wouldn't be able to tell the difference and the unskilled might not be able to tell what it does but ones that keep out (which are more solid) would at the least feel (as in from sense, not just physical touch) more solid than a barrier that doesn't bar entry but rather detects, shrouds, etc. Even if the servant isn't familiar, a magus that's not Rayne would be pretty likely to be able to tell.