  We compare crystal combinatorics of the level $2$ Fock space with the
classification of unitary representations of type $B$ rational Cherednik
algebras to show that any finite-dimensional unitary irreducible representation
of such an algebra is labeled by a bipartition consisting of a rectangular
partition in one component and the empty partition in the other component. This
is a new proof of a result that can be deduced from theorems of Montarani and
Etingof-Stoica.
