So things like backpacks say they count as a factor for Fighter checks (I think, off the top of my head… certainly something does.)
How does that work in conflicts, specifically versus checks? Does the opponent basically get an extra success?
That’s the way I read it.
I interpret it more like that the Fighter test has -1s (which it’s the same as +1Ob).
Stay cool 
You get one less success, I think. Most likely the same end result, but not if you are really dismal and don’t get even a single success on your roll…
Also -1s is different from adding one success to them if you attack and they feint, since their feint doesn’t affect you. So yeah, on second look -1s sounds right.
No one wants to defend that factors are only considered when using factors to generate obstacles and thus are ignored in versus tests?
Drat. I really want that to be the answer… ah well.
If that were true, how on earth would the factor on Fighter for a backpack ever come into play?
-1s. We call it out in a few specific instances. Sorry for the confusion.
Well, that’s why I was hoping it would be the answer.
And thanks for the definitive one, Luke.