During the second step of the encounter, provided the active player put credits on it in step 1, the chosen opponent has no credits. Does this mean the active player will automatically get the reward or is paying 0 credits allowed to force the step 3 test anyway? Yes this came up during a game and brought it to a screeching halt because, as I argued, not paying any credits is choosing not to pay and therefore ends the encounter in the active player's favor, but the opponent argued that since it says to match the amount or pay as much as they can that paying 0 credits counts as paying as much as they can to take the step 3 test. (I won the argument for now but the wording really needs to be "can not pay" instead of "do not pay" if it's going to be clear.)

I would side with you. If “all of their credits” is allowed to be 0, then there is no difference between that and choosing not to place credits. Is there more than one card that invokes this? The only one I found requires both players to put in 5000 credits. So the opponent would have to have exactly 5000 to start with to not have any credits to put in on step 2.