Sat at a zablla proceeding and noticed that the borer from one side was basically listening to the toen and interjecting with some questions, where as the borer from other side was acting just like a toen putting down the case which he prepared with the party who picked him before they came to bias din. They had a toen working for them too. My question is if that is right that one side should prepare his case with his borer who is considered a Dayan with out any one else present and than present that to bias din
The Panim Meiros [2:159] hundreds of years ago wrote that this practice is improper. See also Urim Vtumim, [urim 17:14].
See Shu”t Minchas Asher Vol 2 Siman 99 at the end of the teshuva who discourages zabla for this reason [on a general basis].