When the article calls them
rare, it refers to them as in or at Jerusalem. A souvenir picked up by a
Roman soldier, is possible. But proclaiming the free state of Jerusalem (which is what possession of this coin would mean), could be very hazardous to your
health. I doubt that any self-respecting soldier would do that consciously. _To_me_ more likely is that it was picked up as a coin amongst many, and they (it) were not looked at very closely. It would interesting to know what setting it was found in, where there other coins, or was it a trace find?