The thing with babies and mirrors is that most people have NO idea why it is a minhag. What was the source for the Bubbeh Maiseh (which it totally is, but that does not make it a bad thing – our Bubbies were very wise). We do a lot of things that are Bubbeh Maisehs. But we do them, nonetheless, maybe on the chance that they are right. To me however, if Hashem didn’t say it shouldn’t be done, it probably is safe if we did, so stop worrying about gehennom.
