No. Some individuals matriculate and receive a Cambridge degree without further study or examination and would not be considered alumni.
Due to their position within the University (including Cambridge University Press and Assessment) or a College, they can receive the MA degree, or incorporate a degree that they hold at Oxford or Dublin (Trinity College). Although not considered alumni, as holders of a Cambridge degree they are, however, then entitled to the same alumni benefits as other Cambridge graduates.
Others also matriculate and can hold MA Status during their tenure with the University or a College, but this is not a degree and does not confer entitlement to alumni benefits.1