My Spring-Covenant PCs include a non-Gifted redcap who is the widower of a Gifted redcap and the single father of their three daughters, the eldest of which is a Gifted NPC. Also at the covenant is an ex Miscellanea hedge witch / midwife who is starting to teach the girl stuff...a little of this, a little of that. You know how hedge witches operate. Also at the covenant is a Bonisagus magus who has had several discussions with the girl's father (the Redcap) and the girl's teacher (the ex Miscellanea maga) about maybe taking the girl from the ex Miscellanea maga for a season or so every year or two just to give the ex Miscellanea maga a break and to give the girl a little bit of a different perspective on magical instruction (read "more Hermetic").
The non-Gifted redcap and his Gifted NPC daughter, and the Criamon primus of the Spring Covenant (but not the ex Miscellanea maga) accompany the Bonisagus magus to Durenmar for a Special Convocation at which the Gifted girl garners some attention for her exceptional intellect and courage. An archmage poses a Seeker Question to the attendees and the PCs of my Spring Covenant beat out a nearby Covenant in an Intelligo Certámen, thus figuring out the answer to the Seeker Question. The rival Covenant is quite chagrined.
At the end of the Special Convocation, the Bonisagus maga of the rival Covenant evokes the right of her House to take another magus' apprentice, and calls for the girl. The PCs vehemently object, and argue (in a Bill-Clinton-esque "it depends on how you define 'sexual relations'" sort of way) that the right doesn't apply here because the girl has not received any Hermetic training, and cannot, therefore, be characterized as an apprentice; the Bonisagus maga can't appropriate an apprentice if the apprentice doesn't exist.
The girl doesn't want to be separated from her father, the non-Gifted Redcap. The Redcap doesn't want to see his daughter taken away from him, but doesn't express that aloud, but rather keeps silent, wishing only the best outcome for her. The ex Miscellanea maga who is teaching her "a little of this, a little of that" isn't in attendance at the Convocation. The Criamon Primus and the Bonisagus of the Spring Covenant are the most vocal opponents of the request. And the Bonisagus maga from the rival Covenant puts on evidence to defeat their opposing argument that the girl isn't being Hermetically trained: a witness, to wit, a Merinita maga who was bored during the Convocation and wandered around Durenmar, ultimately strolling into one of its many libraries where she met the girl and saw her reading from a hermetic Tractatus about Herbam magic. When the adjudicator (Murion, Prima of Durenmar) asked the girl about the incident, the girl said (again somewhat ambiguously) that she didn't really "understand" what she was reading, but was drawn to the books because it had a lot of pictures and diagrams of plants in it, which she liked.
Adjudicating this dispute was the LAST thing Murion wanted to do at the closing ceremony of the Special Convocation, and she brusquely ruled in favor of allowing the girl to stay with her Father, DENYING the request of the rival Bonisagus maga to take her away, less on the basis of the Peripheral Code and more as a "courtesy" to the father, who, while non-Gifted, was a member of the Order of Hermes (as was the girl's late, Gifted, Redcap mother).
As a final motion, the rival Bonisagus maga asked that should the girl ever commence Hermetic instruction, that the Bonisagus maga be given the "right of first refusal" -- that is, be given "dibs" on the girl. Prima Murion took the motion under advisement and quickly dismissed the Convocation before anything else cropped up.
Now the rival Covenant is in league with the faeries of the region surrounding the PCs' covenant, trying to spy on them and see if the girl is being Hermetically instructed. Prima Murion informed Prima Bilera of House Guernicus, just to let her know that this dispute was out there. Prima Bilera has tasked a recurring PC (the player shows up only once in a while) to investigate this matter. He's spent enough time in the past at the Spring Covenant to know that the PCs are not being entirely forthright -- that the girl HAS been given SOME Hermetic instruction, but he sees a valid argument in that it might only be considered "de minimus" in light of the fact that her primary instruction so far has only been in midwifery with some magical (and not necessarily Hermetic) elements mixed in.
Is there any precedent in the Peripheral Code involving a dispute of apprenticeship that included a child of a mage of the order?
I think there's a lot of evidence that the Gift runs in some families: notably, House Mercere's few Gifted magi are all descended from Mercere himself. House Mercere utilizes a dedicated campaign of encouraged breeding and the use of spells like Mercury's Blessing (HoH:TL). If we assume that the "average" lifespan of a Mercere magus is about 140 years (lowballing) and there are 12 of them, they need to produce one Gifted child every 10 years to maintain replacements...and that's with them trying and using magic to get results (also, with some coming from Redcap families with Mercere blood and/or non-Redcap families with Mercere blood as well). Given all that, the rate of Gifted children in bloodlines known to produce Gifted offspring reliably is pretty darn low, it seems. I think that this effort to produce offspring is probably the most important factor here because it's a numbers game. Also, most magi gauntlet at age 25, that leaves 10 short years to have children. Having the Gift can make finding a partner for that a bit difficult, too.
I think it's notable that Mercere himself kept his own biological children rather than giving them to Bonisagus, as he did with all the other Gifted he found, and that may form enough of a precedent to act as a loophole. But it's a largely untested one, given how few magi have Gifted children of their own. I think most Bonisagus magi know enough to not try to claim the apprentices of Mercere magi, if for no other reason than to avoid Redcap censure. If the majority of magi come between direct bloodlines, Bonisagus's right will be sorely tested, if not outright altered.