  We construct actions of higher spin fields interacting with gravity on AdS_5
backgrounds such that the Compton scattering amplitudes of the interaction are
tree-level unitary. We then consider higher-spin fields in the Randall-Sundrum
scenario. There, in the fermionic case, we construct a tree-level unitary
action of higher spin fields interacting with branes and linearised gravity. In
the bosonic case we show that this is not in general possible. A tree-level
unitary action of bosonic higher spins interacting with linearised gravity and
branes is only possible in the following cases: The brane is a pure tension
brane and/or Dirichlet boundary conditions are imposed thereby making bosonic
higher spin fields invisible to a brane observer. We finally show that higher
spins in Randall-Sundrum II braneworlds can only be produced by (decay into)
gravitons at trans-Planckian scales. We end by commenting on the possible
relevance of higher-spin unparticles as Dark Matter candidates.
