When the Runner encounters Tollbooth, he or she must pay 3, if able. If the Runner cannot pay 3, end the run.
End the run.
"Ever heard of a catch-22?" "Remind me to forget it."
Tollbooth is a strong mid- to late-game piece of ice. The "when encountered" effect is so strong and the strength is so high that a lot of rules questions come out of players trying to find ways to avoid the toll.
So a cost can be paid even if the effect does nothing, right? You cannot use prevent or avoid effects unless the condition that they are preventing/avoiding is occurring. You could use a non-prevent/avoid paid ability such as on Corroder to spend 1 credit when the Corp rezzes Tollbooth. We will take another look at this scenario before releasing the next FAQ, but that is currently a valid interaction.
Corp has Tollbooth. There is a Parasite on it with 4 counters, making it currently strength 1
Runner has Ice Carver in play and runs. "All ice is encountered with its strength lowered by 1."
Is the ice trashed before the runner has to lose 3 credits? I was reading somewhere about the active player choosing the order of effects, and if it is the runners turn, could he choose to process Ice Carver effect first, then Parasite, killing it before he has to pay the 3
In a follow up question, lets say that there was only 2 Parasite counters on the ice, but the runner has Datasucker in play with 2 tokens on it. "Hosted virus counter: Rezzed piece of ice currently being encountered has -1 strength until the end of the encounter. " That says "currently being encountered", so I think you would have to lose 3 from Tollbooth before you get to use it, whereas Ice Carver says that the ice is encountered at strength -1. The Tollbooth would be trashed before its conditional ability triggered. You have two different constant effects (Ice Carver and Parasite) which combine to knock it off before the Tollbooth can force the Runner to pay credits.
Datasucker counters could not be used until after Tollbooth's ability. "When encountered" conditional abilities are resolved before there is an opportunity to trigger paid abilities.