Turns out, obedience is harder:

In the first place, it seems that Gahl does not consider adequately the role of conscience. Is it sufficient that the confessor enunciates a principle such that it can be assumed that the conscience has been sufficiently enlightened? Perhaps not. Cardinal Newman made an illuminating distinction between a merely notional assent and a real assent of the conscience. It is possible that the penitent does not understand or does not accept the confessor’s admonition and refuses to promise that, in the same situation, he will not act once again in the same manner. The conscience will be enlightened only in the moment in which it has given real assent. What should be done if the penitent does not give real assent to the confessor’s admonition?

Pity the potato farmer who needed to find Denzinger‘s entry on notional assent.