The architect does need to properly design the details of the membrane and the flashing, and there should be some oversight that the details are being installed correctly.
But new North American Test Standards for rainscreen assume an imperfect membrane and will design failures in the backup wall (usually will design a series of holes in a sheet of plexiglas) so that the performance of the system joints is what is being evaluated, not the membrane itself.
Going thru the scope of these details with the contractor will also highlight their importance (but as you say, there is no guarantee without oversight).
