In Insights to daf 36, paragraph 2 regarding the b'racha on tefilin shel rosh, Rabbi Dicker brings the Kitzur Shulchan Aruch and the idea of an "Amen L'vatala". Is "L'vatala" the actual language of the Kitzur Shulchan Aruch? Contrary to that, I've heard many people say "Amen" to all sorts of things - when wishing someone long life on Rosh HaShana, many say "Amen"; even when making a L'chaim and adding a few words of blessing (not b'racha), people say "Amen". Is there a specific isur of Amen L'vatala, or is it just good advice to be "stingy" with Amen? In either case, is there a source for the Kitzur ruling this way?
Good point. You are correct that the usage of the term "Amen l'Vatalah" is not accurate. The Kitzur Shulchan Aruch (10:4) writes, quoting the Pri Megadim, that "since there is a Safek in this Berachah, there is also a Safek whether the listener should answer Amen or not." The problem with this Amen is that one should not say Amen in response to a statement that is not true, incorrect, or prohibited to say. If the Berachah itself is not mandated, then saying the Berachah constitutes mentioning Hash-m's Name in vain, which is prohibited. Consequently, one may not answer Amen to a Hazkarah l'Vatalah of Hash-m's Name; by saying Amen, one is acknowledging that the preceding statement is true and good -- and a statement which contains Hash-m's Name l'Vatalah is certainly not good.
Accordingly, to say Amen to a friend's Rosh Hashanah greeting (or any personal blessing of that sort) is certainly permissible (and is even commendable). (For more on the topic of saying Amen to personal blessings, and the exact meaning of Amen in this context, see (or rather, listen to) my audio lecture to Shevuos 36, entitled "Amen -- As Good as the Original?" ( http://www.dafyomi.co.il/lectures/marei-shev036.htm )
With warm regards,