* However, the Shach YD 266:18 argues on the Rashbetz that the Baal HaMoer would permit just like it’s permitted to board a boat on Friday for the purpose of a mitzvah (S”A OC 248:1) and Brit Milah is a tremendous mitzvah. The Magan Avraham 331:9, Mishna Brurah 331:33, and Sh”t HaRanach 38 (quoted by Tzitz Eliezer 12:43) agree with the Shach.
* The Chida in Birkei Yosef 248 quotes several achronim who defended the Rashbetz by saying that it was only permitted to board a boat on Friday for a mitzvah if one stipulated with the group that they wouldn’t continue to travel on [[Shabbat]] (S”A 248:1) and since there’s no way to make such a stipulation regarding Milah it’s forbidden to do it within 3 days of [[Shabbat]] like the Baal HaMoer.
Yabea Omer YD 5:23, Menuchat Ahava (vol 1, 1:6), and Rav Mordechai Eliyahu (comments to Kitzur S"A 163:4) accept the Chida as halacha.
* However, the Sh”t Tzitz Eliezer 12:43 rejects the Chida because he points out that the Tashbetz himself wasn’t sure whether to hold like Rebbe that one must stipulate or Rabben Shimon and one wouldn’t have to stipulate and only as a stringency did the Tashbetz hold like Rebbe. The Tzitz Eliezer concludes that it’s illogical that the Tashbetz would have postponed the Milah from Thursday just because of a stringency of holding like Rebbe. [See further in the Birkei Yosef who gives a second defense of the Rashbetz and Tzitz Eliezer who rejects it as well.] </ref>
# Everyone agrees that if a baby boy is born during the [[Ben HaShemashot]] (halachic twilight) on Wednesday can have the Brit Milah on Thursday next week. <Ref>Menuchat Ahava (vol 1, 1:7) and Sh”t
Yabea Omer YD 5:23(4) explain that since the Brit Milah’s original time was set for Thursday because of a doubt it’s not considered like it was delayed specifically for that time. </ref>