Q. If someone eats in a kiddush or an after davening lechaim for a yohrzait, where mezonos are also served, and eats standing up is he considered as pasul leidus or unfit to testify?
A. Talmud (Kidushin 40b) teaches that the one who eats in the marketplace (or a public street) is disqualified from testifying. Shulchan Aruch (C. M. 34: 18), rules that disgraced and befouled individuals, are ineligible to testify and they are the ones that eat in a marketplace in front of many.
Mishne Halochos (5: 15: 61) maintains that those who walk around at wedding receptions or similar public eating affairs carrying a plate, especially if it is a mixed affair, even though it isn’t exactly a marketplace, it is still similar, one has to refrain from inviting them to be the witnesses necessary for the wedding.
He quotes a known story of the Shoel Umeshiv, who during a market fair was gazing through his window and observed a fellow eating in the street. The Rov send his Shamesh to fetch him and questioned him from where he was. When he answered that he was traveling from Krakow, he asked him to please take a letter back to the Chief Rabbi of that city, which he happily accepted to take. The Shoel Umeshiv wrote the letter and sealed it, so the carrier won’t open it and gave it to him. When the Rov af Keakow received the letter from the Soel Umeshiv, he immediately wondered why the great Gadol Hador would choose such a lowly individual, that he knew well to deliver it. The answer came when he read the message it carried, namely, not to engage the carrier as a witness in anything, since he observed him eating in the public marketplace.
One may argue that eating at a kiddush after davening standing and walking around may be similar, however, Horav Shlomo Miller’s Shlit’a opinion is that it is different and since it is traditional to do so in many a shul, although it is preferable to sit down, if one does not, it does not disqualify one from being a witness.
(See Devareicha Yair 2: 34, Gam Any Odecha, 40 and others) regarding eating in a public bus or eateries facing the street).
Rabbi A. Bartfeld as advised by Horav Shlomo Miller and Horav Aharon Miller Shlit’a