You see, the problem is that, in Judaism, a practice which is done for a very long time by a lot of people becomes something like law. It isn't really law, but it takes on the same power. So, should we consider these superstitions as valid acts? Required acts? Or, should they be forbidden, because, officially speaking, Judaism frowns on superstition (since it's, in essence, a power other than God)?
The answer is, at first, a very reasonable one. Any practice which has a rational, reasonable basis should be continued. In other words, if something is done because of a superstition, but it also happens to makes sense, we don't outlaw it just because it's a superstition. Great! Makes perfect sense. Until, of course, we get to their first example:
Some people have the custom to ensure not to walk over a baby or child, and to require somebody who did walk over a baby or child to walk over him again, backward. The Be'er Moshe writes that this is, indeed, a legitimate practice that is based upon a valid reason. There is a concern that walking over a child will have the effect of stunting his growth, and therefore if one did walk over a child, he should walk back over him to eliminate the effect. (Accordingly, there would be no problem with walking over a person who has already grown to his or her full height.)
Sigh. As I said to someone recently: Logic. It's like nuclear power. It can accomplish great things. But, in the wrong hands, it can create disasters. Not everyone should be allowed to use it.