Quantum fields as Cosmic Censors in (2 + 1)-dimensions

We discuss the effect of quantum fields on classical background spacetimes which contain timelike singularities. We do so for the case that the background is a [Formula: see text]-dimensional BTZ spacetime, whether corresponding to a rotating black hole ([Formula: see text]) or to a naked conical singularity ([Formula: see text]). In the black hole case, scalar quantum fields render its Cauchy horizon unstable, while for the conical geometry, they produce a horizon around the naked singularity. Thus, quantum effects improve the predictability of the spacetime acting as effective Cosmic Censors.