While it's true that the Law as a philosophical discussion is not dependent on punishment, the Law as philosophical discussion ends at the classroom door. Once we are in society, in "(mythic) real life", the realities of law, what is merely "technically illegal" vs what is "actually punished" are quite, quite mutable. And involved in that practical (vs. theoretical) social distinction are such variables as popularity (do we care about this one?), personal interest (ie, "do we really care?"), practicality of enforcement (ie, "is it really worth the trouble/effort?"), practicality of prosecution (ie, "yes, we believe/know they did it, but can we prove it?"), and cost/return of such prosecutions (ie, "Do we have better things to worry about?"), and other, practical concerns (not the least are political and social considerations!).
On another board, I once got into a heated debate (:shock:) with someone who claimed to be a lawyer, but seemed to be oblivious to the fact that real, living breathing people decided which cases to prosecute, and which to ignore, people with prejudices and headaches and careers and all the things that distinguish theory from practice.
A mage innocently casts an Intellego spell on a group of peasants. In that group is a disguised Hermetic Mage. Has that first mage broken The Code, by using Hermetic Magic to peer into the affairs of a fellow mage? Technically, yes, absolutely! Do we think much will come from prosecuting him? No, not so much.
Another mage casts the same spell on purpose on a suspicious character skulking about their covenant, a character who seems to know magic. NOW do we care?... Meh... it depends.
The same 2 magi, but the first casts it while the second is in his home covenant, minding his own bussiness. NOW we care.
Why? Same rule has been broken in each case, but... it's never as clear cut as it is listed in The Code. "Illegal" is not an issue that stands as virginal from practical realities as it at first pretends, and it never was meant to. It gives guidelines, not tight definitions. On the one side, there is latitude for forgiveness before it even goes to trial, and on the other, there is wrath for someone who gets cute and thinks that sophism can provide an exception to the spirit of the law.
The Code is Swiss cheese, but that doesn't mean it's broken. It just means that you don't want to get close to the boundaries it sets, OR you need to accept the possibilities if you get singled out. *
(* Which gets back to the whole idea of being smart enough to "not get caught", or at least not be blatant about it. If you don't send up flares, a Tribunal is less (relative term!) likely to deem you a danger to the Order; if you bungle, then censure is more likely to be meted out, if only as preemptive self-protection.)