I think i know this answer, but i have never seen anyone be stringent on this. What is the rule here and how do people play this? Can the reactive hacker reset if the active model does idle-brainblast and they dont want to brainblast/blackout/oblivion/whatever hacking program back? Or is the reactive model model FORCED to use a hacking program to defend itself?
You can always declare a Reset if someone triggers an ARO: http://infinitythewiki.com/en/Reset In his Reactive Turn, the trooper has an enemy declare or execute an Order in his Zone of Control. Wouldn't a Hacker usually want to ARO with a Hacking attack back though?
If they are inside your ZoC, yes you can reset. If they are hitting you through a repeater, you can only reset if the Active model performed Idle using stealth. If they did, you get no ARO until they declare you the target of their hacking attack, then you can reset. If they didn't use stealth, you get an ARO but the requirements for reset are not met, so you would have to respond with a hacking program or not at all.
Apologies, I'm wondering through a repeater and not where each otherwise in ZoC. And hacking through an enemy repeater gives -3 mod that may be prefered to avoided.