[ While Thancred does not know all the specifics of what those assistant mages are meant to do for Yennefer and what the expectations are, it does sound as if they have some choice as to whether or not to remain under her watchful eye. As their focus is on alchemical mixtures rather than spell-weaving, it explains how she's been able to maintain the secret of her magical inability.

He gives a small shrug when she insists that Borrel had suited him. Were it not for all the circumstances surrounding it, he would not be opposed to spending more time there.

He spears a piece of roasted tomato with his fork, letting it hang in the air for a moment as he considers her question. ]

I'd heard talk around the castle that the queen had made a trip there. I suppose I wanted to see what all the fuss was about. As it turns out, she had gone to visit family.

[ Which all sounds harmless enough on the surface, until one realizes that her uncle is highly ranked in Thorne's military. ]