 It is quite unlikely that this may be construed, with intermediate accommodation in c1, which is the antecedent of the conditional, as “If Fred is married and is coming to the reception, he may bring his wife.” More generally, we don’t know of any clear-cut cases (i.e., cases in which accommodation is not forced by independent contextual factors) in which a presupposition triggered in the consequent of a conditional is accommodated in the antecedent.