1) The Mishnah Berurah 88:7 writes that a Nidah should not look at a Sefer Torah when it is lifted up to show to the people. This applies also for ladies who are Nidah because of the Chumrah.

2) The Sefer Hachinuch Mitzvah 207 (end of paragraph beginning Zot Haiytah Takanato Shel Rabbi Zeira) writes that the Sages saw that this is a good, necessary, Chumra and agreed to the daughters of Israel.

It is true that the chumra has an effect on others. For instance, the husband wants to fulfil the Mitzvah of having a lot of children, and the chumra of the ladies may sometimes make this more difficult. However, the daughters of Israel saw that all the complicated Halachot of Zavah etc, (for instance the difference between one day of Zavah or 3 days) are too difficult for the average woman to keep up with properly. Therefore they made a necessary chumra. After all the wives are responsible for keeping the dinim of Nidah, and they saw what is essential in practical everyday terms.

Shabbat Shalom

Dovid Bloom

Follow-up reply:

3)

(a) The Gemara Yevamos 102a states that if Eliyahu will come and say that one may not perform the Mitzvah of Chalitzah with a sandal he will not be listened to, because the custom is to do chalitzah with a sandal.

(b) The Meshech Chochmah in Parshat Bechukotai Vayikra 26:44, at the end of the paragraph beginning v'Af Gam Zot, explains how the leaders of every generation made Gezerot in order to protect the Jewish people and the Torah. He cites the Talmud Yerushalmi that even Eliyahu cannot annul these Gezerot.

(c) Meshech Chochmah explains that what this means is that as long as the Redeemer has not come, and the subjugation to the nations has not yet ended, even if the herald and harbinger has already come and announced that the Mashiach will be here soon, the Gezerot will not yet terminate, because the gezerot of Chazal are what keep Klal Yisrael going.

(d) The sefer Dudaei Reuven, on Parshat Ekev page 198, by Rav Reuven Katz zt'l the Rav of Petach Tikvah, writes that when the Mashiach will come there are gezerot that will be annuled. For instance if the gezera of Rav Zeira will not be annuled no one will never able to bring a Korban Zivah. However, before the Mashiach comes, even if Eliyahu Hanavi has already arrived and told us that the Mashiach is almost here, all the Gezerot will remain intact.

Dovid Bloom

Explicit source in Meshech Chochmah:

The Meshech Chochmah writes in Parshat Bo Shemot 12:22 (pargaraph beginning v'Atem Lo Teitzu) that the Halacha Pesuka of Rav Zeira that the daughters of Israel are stringent .... will be annuled in the time of the Beit Hamikdash because otherwise ladies will not know when to bring a Korban Zivah.

Dovid Bloom

Correction:

1) I wrote in my first reply; in 1); that a Nidah, even only according to the Chumra of Rav Zeira, should not look at the Sefer Torah when Hagba'hah is done in shul. However this is not true, because the Rema, in siman 88 that I cited, writes that the custom to be stringent on these matters does not apply on the days of "libun"; literally "white" (clothes); when there is not actual bleeding.

2) However, I do have a different suggestion of a slightly wider ramification for the Chumra of Rav Zeira. This refers to the practice of wearing special clothes when she is Nidah, mentioned in Shulchan Aruch Yoreh Deah 195:8. The Taz Yoreh Deah 1:22 writes that it is sufficient to change only a small item of clothing. Some women nowadays also practice this custom, which applies all the time, even on the days when she is tamei only according to Rav Zeira's chumra, and not only when she is with her husband.

Shavua Tov

Dovid Bloom