  We revisit the question of the contributions of Planckian quantum black holes
in general and of remnants in particular to low energy physics observables. As
long as quantum gravity preserves the symmetries of the low energy effective
field theory, we find that the bounds on the number of quantum black holes or
remnants are very weak. Typically we rule out using data on the anomalous
magnetic moment of the muon that there are more than $10^{32}$ quantum black
holes coupled to the standard model particles gravitationally. Remnants thus
remain a viable option as a solution to the information paradox of black holes.
