Are Dynamic Shifts Dynamical Symmetries?

Abstract Shifts are a well-known feature of the literature on spacetime symmetries. Recently, discussions have focused so-called dynamic shifts, which by analogy with static and kinematic shifts enact arbitrary linear accelerations all matter (as well as change in gravitational potential). But mathematical formulations these breaks down: while shift act field, acts structure instead. I formulate different, ‘active’ version does matter, analyse consequences this reformulation for Newton-Cartan Theory Maxwell Gravitation.