Reply To: Al Tarbe Sicha Im Haisha

What “grey area”? Shaking hands is a yehareig v’al yaavor issur d’oraysa of arayos. No one near the stature of Rav Moshe, the Chazon Ish, the Steipler et al dispute this. Would you be be oiver a sofek chillul Shabbos because there is an opinion that it is ok? If offered a chicken-and-cheese sandwich — which is only a D’RABBONON — would you eat it to avoid embarassing the person who offered it?

But a YVY yes?