"Oh man, I'm gonna miss these openings when you learn too much ot make them" He grins, then grows somber, "A geasa or Ban is a pronouncement with all the power of the dreaming behind it that enthralls your actions. You do not get to Oath. You do not get a choice. If a Noble of sufficient power to do so declares that you never speak again... your tongue grows as lead...and trying to fight it can weaken you and lead to death. A ban can keep you from ever going home again lest your feet burn with every step. I'm not saying every noble whips that out, or can, but when our safety as a species is on the line? Yeah, they sure don't feel too much guilt about it. Other options DO happen, of course. In the old days you might have been made a man servant for decades... and then released finally when a world had forgotten you. Your memory could have been wiped, or arrangements could have been made to have you seen as insane and put in an asylum where our secrets would not be taken seriously."