I am wondering if the following scenario would work under RAW.
Two Tytalus magi wish to test out their combat magics/prowess on each other, and are prepared to risk their lives in the process.
So they declare Wizard War on each other, possibly something about irreconcilable differences on the doctrine of war. They declare they will both bring supporting combatants, and also have pre-arranged that no other Hermetics will be in their isolated, chosen field of battle. So that anybody found at the field of battle is considered a valid target.
Then for a month, or until mutually agreed, throw their armies and magics at each other, in happy slaughter.
They will want to make sure that the Quaesitors accept their field of battle. Once accepted, they will for sure want to make it widely known to other Magi that the area will have open magic warfare happening, if for no other reason than any that happen to show up in the area will have knowingly entered an area in which a Wizard War is being fought. If the general population of Magi in their Tribunal do not know about it and enter the area, attacks on them could very well be considered a crime against the Code.
They also might want to get one of the Quaesitor to serve as referee or observer. If nothing else, this would provide them some protection if another Magi happens to enter the area and gets blasted. "It is no crime, since they knowingly entered an area of declared Wizard War."
It would require some odd rulings or exceptions within the tribunal, since usually a wizard war is marked by the designated participants, not a designated area, and you are essentially declaring an area a forfeit zone where wizards forfeit their rights by entering.
If the two combatants arrange, before the Wizard War is declared, that no uninvolved Hermetics will be in the chosen battlefield. Negotiations, bribery, intimidation, Certamen, etc.
And can convince the Quaesitores that they have made adequate preparations, is there any reason two groups of magi can't attack each other if they are all voluntarily waiving their rights towards each other?
(I am assuming that their apprentice will be involved )
I know most Qs will want to restrain such "lawlessness" . Can magi voluntarily waive their rights?
The magi can't attack each other outside of a lawfully declared Wizard War, period. It's in the Oath, and the Oath is taken very seriously.
They're perfectly welcome to arrange said Wizard's War to their satisfaction, though; nothing in the oath says they can't. On the other hand, those arrangements cannot force uninvolved magi to forfeit the protection of the Code, unless the area is clearly marked as a Sanctum of one wizard (and meets any additional requirements for a valid sanctum in the particular Tribunal's Peripheral Code), and I would bet bezants to groats that at least one extra Tytalus would take a stroll through the area just to be a dick force the issue.
This is a very interesting question, but I don't think it applies, actually. The code is mostly written such that magi have a duty to act accordingly, not that they have a right to expect other magi to act accordingly, e.g. you don't have a "right not to be scryed upon" that you could theoretically waive; every other magus has a duty not to scry on you, and you can't personally grant them permission to abrogate that duty.
A magus can say “I will happily submit to answering these questions under the effects of frosty breath of the spoken lie.” Not to mention the wizards war itself is a waiving of one’s own rights to protection under the code So at least in some specific situations it is perfectly fine and possible to waive ones rights.