A fast view to the FAQ for Sappers is what lead to the post
While the question posed there doesn't directly address what I posted above, I do believe that it implies only the target hex's combat reductions are ignored. But, I like having solid examples to be sure.
The text on the Sappers card is unambiguous: "all terrain combat reductions are ignored", but from the FAQ, it seems what is meant is "all terrain combat reductions
due to the targeted hex are ignored". What the question on the FAQ was directly asking is whether or not Sappers would allow a unit that enters a forest hex to now battle, where without the play it would not be able to do so. Nothing on the card suggests that is possible (unless one equates "reductions" with "restrictions", which I've certainly been known to do
), but good to talk about it to be certain.
The FAQ in question:
Q: Does the Sappers benefit from battle out- and inside? Are units allowed to battle if they move onto a terrain, which prevent normal battles?
A: Only when the enemy unit or leader is on terrain will the Sappers card work. (Only into - target hex)
Playing the Sapper card will not allow an infantry unit to enter a forest or town and still battle.
(Richard Borg: 2015 - June - 22)