This thread wheeled forward at a pace
Sorry One Shot for my quick and dirty reply, I could've phrashed it better, you do have a great depth of knowledge to where to go poking for rules/writings on most anything published in your mind; however the intepretation of it is as always up to the troupe involved, saying somethings impossible because vague rule with different intepretations makes it so under your idea for how ars should play makes for only circular arguments, A says no, B says yes, A says no because Z1, B says Z1 rather be read as Z2 and so on.
Now:
'magical senses' and 'hearing' in items you take the stance raw contradicts the supplements, referencing granting magical senses(which is a section so poorly written noone, not even our local one shot, ever bothered about it to my knowledge, it feels like with you a touch version of 'shriek of impending shafts' for grogs would be a magical sense granted and in need of atleast three other arts to make work with alot of debate?) wheras I take the stance 'supplements expand upon possibilities and I cannot see anything realy wrong since pushing against a surface, can we truly say the surface wont feel you pushing down into it? What determines the ability to 'feel', a rock you squeeze in your hand might not be able to say 'Ouch' but who can say it does not feel your touch?' It is /magic/ thus it works, the spell imbues the item with the ability to 'feel' a touch for its triggering, or the vibrations of sound as 'hearing'; equal and opposite counterreaction and all that' #magicismagic
Also you take the viewpoint 'a spell does not exist till its fully formed and then it has its effect' where we tend to see it as... lets say easy example... ball of abysmal, mage does some words and gesture, a fireball forms in his hand and its slung at you; hands of grasping earth, the earth starts to swell and flow into the mold of said hands. Hitting that 'forming spell' with a counterspell, be our guest, or hitting that ball of abysmal cosmetic effect with a jet of water you mastered? Fine, the spell is not in effect till the cosmetic effect hits you. Sorta. It feels more magely and wizardly and in truth more Gamey, more Fun Cosmetic effects might do away with some grayzones as to 'why does ball of abysmal need to be finesse thrown if I could just set the target on fire without throwing a fireball? why is it easier?' but it removes some of the charm; come on I want to roll for my fireballs to hit again
So if there are no magical energies forming and sweeping closer, "slowly" taking form, but rather instantly coming into effect once a sequence of "magical words and gestures" are completed; then sure, then you cannot counter anything with a PeVi counterspell, its already in effect, you'll get burned before you cancel the momentary flame. If one does see it as magic "slowly"( a round isnt slow but w/e) forming, being able to put up a quick brick wall to ward of an incoming spell before it reaches you splashing across its surface; Rather than just 'ehm, I correctly identify the spell as a CrIg I choose ReAu as my defense, I roll to fast cast defense, I endup after subtracting ten and dividing by two with a total of 18, this is enough to defend against a lvl36 spell; Good job, you defended well. next round please, choose your actions, as little description and creativity as possible, remember we go about this as calculators following the strict procedurals'.
Basicly you give me the feel of the later, much like our local one shot can be Terribly sorry if I'am reading you wrong. If its truly impossible to do something then one can mention it, but if not and its cool and enables someone to go in a direction they want then thats fun, that story weighs heavier than a reading of the rules that makes it impossible on some technical little detail. =)