  We consider a 2D quantum spin model with ring-exchange interaction that has
subsystem symmetries associated to conserved magnetization along rows and
columns of a square lattice, which implies the conservation of the global
dipole moment. In a certain regime, the model is non-integrable, but violates
the eigenstate thermalization hypothesis through an extensive Hilbert space
fragmentation, including an exponential number of inert subsectors with trivial
dynamics, arising from kinetic constraints. While subsystem symmetries are
quite restrictive for the dynamics, we show that they alone cannot account for
such a number of inert states, even with infinite-range interactions. We
present a procedure for constructing shielding structures that can separate and
disentangle dynamically active regions from each other. Notably, subsystem
symmetries allow the thickness of the shields to be dependent only on the
interaction range rather than on the size of the active regions, unlike in the
case of generic dipole-conserving systems.
