I wouldn't call it so much dishonest as I would ill-informed. Modern combat the likes of which we saw in WW2 was often hectic enough that it was difficult to confirm kills - if 4 Shermans shot at a Panzer IV and then the crew was seen to bail out or the vehicle to "brew up," it was likely that each crew would assume that their shot was the one that took the enemy down.

(I'll try to find page numbers for this but I remember reading it in Armored Thunderbolt)

Aircrew had a very similar problem actually - one of the biggest issues facing 8th Army Air Force statisticians was trying to figure out how many aircraft the Eighth's bombers were taking down, as the destruction of the Luftwaffe was imperative for the success of OVERLORD. Trouble was, for every Messerschmitt or Focke-Wulf shot down, there'd be upwards of 10 gunners who'd shot at him and all would claim the kill. Kill claims were usually rounded down to about a third.

(Don Miller, Masters of the Air)