Responsa for Bava Batra 300:13

When Rabbi Zamlan was ill he sent for Rabbi Asher in order that the latter help him dispose of his property in a manner that would make it impossible for his wife, L, to appropriate his possessions in payment of her ketubah or for her sustenance. Rabbi Asher refused to come, but Rabbi Zamlan implored him and pleaded with him saying: "What can I do for my only son who, after my death, will have to go begging from door to door?" Rabbi Asher then agreed to act as a witness, and Rabbi Zamlan gave away to his son and to other persons, all of his property as an outright gift effective immediately. After his death, L's relatives summoned Rabbi Zamlan's son to the court of Rabbi Perez. The latter recorded the claims of the two parties and sent the claims to Rabbi Meir without giving the names of the litigants and without expressing any opinion on the subject. Rabbi Meir ruled that L was entitled to collect her ketubah, or to draw her sustenance, from the possessions of Rabbi Zamlan which he had given to his son; his reason being that even an outright gift to an heir is considered an inheritance and that the widow's ketubah is a lien upon it.
Rabbi Perez took issue with Rabbi Meir quoting Alfasi's decision that the ordinance of Usha — which ruled that a person who divided all of his property among his children may derive his sustenance as well as that of his wife's from such property — was not accepted.
Rabbi Meir reproved Rabbi Perez for resorting to Alfasi when the Talmud specifically decided that the ordinance of Usha was not accepted. R. Meir contended, however, that only that part of the ordinance was not accepted which gave the right to the donor, and to his wife while he was alive, to derive their sustenance from the property he had given away; while the rule that the widow may collect her sustenance or her ketubah from such property after the donor's death, was accepted before the ordinance of Usha was promulgated, and has remained in force independently of such ordinance.
Meanwhile L's relatives have written to Rabbi Meir asking for his decsion in this matter. R. Meir answered that he usually refrained from sending legal opinions to litigants, or to their relatives, and confined his responses to judges. But, when Rabbi Perez, in his second letter, gave the names of the litigants, R. Meir realized that the letters from L's relatives dealt with the same case. R. Meir recalled that among these letters was found a letter from Rabbi Asher which explained the circumstances of the gift mentioned above. Therefore, R. Meir added (in his second letter to Rabbi Perez) that since according to Rabbi Asher's letter, the donor mentioned the contingency of death when he summoned Rabbi Asher, he therefore made the gift to his son causa mortis (cf. B. B. 151a), and a widow is undoubtedly entitled to collect her ketubah from causa mortis gifts.
SOURCES: Cr. 192; Am II, 46–7; cf. Hag. Maim. to Ishut 16, 4; Mord. Ket. 161. Cf. Agudah B.M. 29; Moses Minz, Responsa 66.