A rotating frame of reference is a special case of a non-inertial reference frame that is rotating relative to an inertial reference frame. An everyday example of a rotating reference frame is the surface of the Earth. (This article considers only frames rotating about a fixed axis. For more general rotations, see Euler angles.)
If a spin 1/2 particle we're to be rotating as it was passing through a Stern Gerlach experiment wouldn't this create particle paths which may switch from spin up to spin down or vice versa, or even oscillate in mid flight?
If the experiment were done with a rapidly rotating silver atom source...