  In a recent paper [J. P. M. Pitelli, Phys. Rev. D {\bf 99}, 108701 (2019)],
one of us showed that the vacuum state associated to conformal fields on a
Poicar\'e patch of anti-de Sitter spacetime is not $\text{AdS}$ invariant for
fields satisfying non-trivial boundary conditions (by non-trivial we mean
neither Dirichlet nor Neumann) at the conformal boundary. In this way, two
isometrically related observers in anti-de Sitter space have different notions
of no particle content. Therefore, an observer who is suddenly transported to a
different (but isometrically related) frame will feel a bath of particles. This
process contradicts our intuitive notion based on our experience in Minkowski
spacetime, where the vacuum is Lorentz invariant, and no particle is produced
between boosted frames. We show that the total number of produced particles is
finite, but grows without limit when we approach (via isometric transformation)
Dirichlet or Neumann boundary conditions since in these cases the vacuum is
invariant.
