Who won that round ?
He had Rav Dovid Cohen who agreed with him that many of the tznius guidelines such as long skirts , type of material etc. are opinions of poskim rather than clear halachos with a mekor, but pushed back when Lichtenstein suggested that based on a teshuva of Rav Moshe allowing a tefach of hair to be uncovered etc. there is no obligation to follow guidelines that are machmir , pointing out to Lichtenstein that in places where this is the accepted mode of dress, to dress otherwise becomes assur....
Somehow Rav Falk never made it onto his show....