Milhouse,
1. That is darchei Emori (a superstition rooted in a”z).
2. Compare the Mishna Berura on Parashat HaMan (1:13).
3. The baby is protected by his parents’ merit.
4. You prove my point. If the mezuzah is not a mitzva it is its message.
6 Please cite the place in the Gemara. I cited Rambam to the contrary. Of course, if someone thinks it protects it might have a placebo effect.
7. What about people who have kosher mezuzot who suffered? What about those Jews who were dragged out of their homes by the Nazis ym”s?
Laskern, actually it was the Gra who did not sing Shalom Aleichem.