Is the peculiar spatial nonlocality of the “standard” arrival-time distribution an artifact of using a nonrelativistic approach?

Using the relativistic arrival-time distribution of Kijowski it is argued that the peculiar form   of the spatial nonlocality—but not the nonlocality itself—of the “standard” distribution is an artifact of the nonrelativistic approximation. Also spatially nonlocal is the related local momentum density based on the symmetrization pˆ(X)=pˆ1/2|X〉〈X|pˆ1/2.