Should laws be passed without intent to enforce them?

[buritobr]

No, but I know that many people support this kind of law in some situations.

Example: According to Brazilian law, it is considered a crime an adult offer alcoholic drink to <18 kids, even inside private homes. However, no public authority can enforce this law inside private homes, because a public authority cannot get inside a private home without the consent of the owner, unless there is authorization of the justice or emegency situation.
In many family sunday lunches, teenagers drink a glass of beer or wine with their parents. I think it is better that the kids start drink with their parents and not with their same-age friends, because they learn how to control themselves. They learn how to enjoy the taste of the beer or the taste of the wine, and not the alcohol. However, according to the law, these parents are committing a crime and they might be jailed. But the law cannot be enforced.
I think that the law should be changed so that teenagers can drink beer or wine inside private homes under the responsability of their parents. However, even many parents who offer drinks to their kids want to keep this prohibition. They think that the law shows the society that teenagers drinking is bad, and that a glass of beer/wine in the sunday lunch is only an exception.