The terms are merely hospitality.

[ she inches forward on her side of the bench. and she places a second lemoncake gingerly upon the centre of her own plate. ] Where I am from, the guest right is a staple every visit.

[ perhaps she wouldn't ordinarily know that it needs explaining...except that she's been here long enough, spoken with enough non-westerosi, to know what they hadn't yet learned. ] Guest and host share bread and salt, and that act binds them in hospitality. Neither will let harm befall the other so long as they share their roof.