Comment on "The entropy of a hole in spacetime"

Balasubramanian, Czech, Chowdhury and de Boer \cite{BCCdB} studied a “spherical Rindler space” and found that accelerating observers are causally disconnected from a spherical region located at the origin of Minkowski space. We show that there is no any horizon of size $R_0$ (which is related to the chosen initial conditions) and the event horizon at $r=0$ is obtained only from the two-dimensional ($r,t$) static restriction. Their near-horizon geometry cancels the time dependence of the original metric and therefore the approximation used is doubtful.