But I checked it (easy, just try to resign a game with contact and with no checkers in the opponent's home board, then don't confirm the resign), and you were right, only a gammon is awarded in that case. Somehow my memory played a trick on me, sorry for confusing the debate.
Now it is also true that it seems near to impossible to think of a position with no checkers in the opp's board, where one would be better off resigning a gammon. But IMHO the possibility to do so is still a conceptual bug. And indeed, here is a somewhat contrived situation where it can turn into an exploit :
Triple gammon tournament, there is only one game left to play between the leader and the second. The leader is 4 points ahead of the second, so that he wins the tournament unless he loses a backgammon. To avoid that, he manages to leave the opponent's home board, resigns and wins the tournament. That's wrong.