  We revisit the arguments underlying two well-known arrival-time distributions
in quantum mechanics, viz., the Aharonov-Bohm and Kijowski (ABK) distribution,
applicable for freely moving particles, and the quantum flux (QF) distribution.
An inconsistency in the original axiomatic derivation of Kijowski's result is
pointed out, along with an inescapable consequence of the "negative arrival
times" inherent to this proposal (and generalizations thereof). The ABK
free-particle restriction is lifted in a discussion of an explicit arrival-time
setup featuring a charged particle moving in a constant magnetic field. A
natural generalization of the ABK distribution is in this case shown to be
critically gauge-dependent. A direct comparison to the QF distribution, which
does not exhibit this flaw, is drawn (its acknowledged drawback concerning the
quantum backflow effect notwithstanding).
