Questions regarding the Eiruv

Q: If the Eiruv is checked before Shabbat and is declared Kosher, should a person still be concerned that it was rendered invalid on Shabbat in the event of a storm? Can we rely on the "Chazakah" (presumption) that since the Eiruv was operational the beginning of Shabbat, it still remains that way?
A: It depends on whether the Eiruv is strong or not. This is a most serious question, and one should ask the Rabbi who is in charge of the Eiruv.

Q: If an individual actually knows with certainty that the Eiruv came down, should he tell other people, or keep quiet about it since they may not listen? Is this a case of "Mutav sheyeeheyu shoggegin v'al yeeheyu mezidin" (It is better for people to transgression unwittingly than wittingly)?
A: In general, the whole issue of an Eiruv is Rabbinic since we are discussing a "Karmelit". Therefore, if people will listen, one should inform them. If they will not listen, we apply "mutav she-yeeheyu shoggegin…" (see Rama, Orach Chaim 608:2 with commentaries).
Ha-Gaon Rav Avraham Dov Auerbach, Av Beit Din (Head of the Rabbinic Court) of Tiveria, once told me about an incident that occurred there in the past.. One time the "eruv" was damaged, and the Rav of Tiveria ruled that the "eruv" was kosher. There was a great Torah scholar who lived there and he bumped into the Rav of the city after Shabbat. They talked, the Torah scholar walked him home, and they sat and chatted. The Torah scholar said, "Let's learn some Torah." The Rav of the city obviously agreed. The Torah scholar took Massechet Eruvim and they learned. Suddenly, the Rav of the city said, "Oy va-voy! If so, I ruled incorrectly today!" The Torah scholar said, "It appears so." The Rav of the city asked, "Did his honor announce in his shul not to carry on Shabbat?" "No," he responded, "since carrying in this place is a rabbinic prohibition, but honoring a Torah scholar is a Torah mitzvah. I therefore did not say anything."

Q: If someone makes an announcement on Shabbat recommending that the Eiruv not be used because of the possibility the Eiruv came down (without having any knowledge that it actually is not valid), how should the community behave? Should this announcement be ignored, or once it is said, people should be careful not to carry?
A: One should ask the Rabbi in charge of the Eiruv.

Q: Does the Rav have any specific tradition from Ha-Rav Tzvi Yehuda Kook regarding the use of an Eiruv on Shabbat?
A: In the book "Ki Shem Hashem Nikra Elecha" by Ha-Rav Shlomo Gilat (p. 66), he relates that Rabbenu Ha-Rav Tzvi Yehudah did not carry things out on Shabbat within the Eiruv, but he agreed that a student could carry the house key.