When you look at a legislative provision such as section 139(1), you then need to look at the remedy or consequences that may flow from the breach.
The note to section 139(1) says that a by-law (that is harsh, unconscionable or oppressive) may be invalidated by the Tribunal.
So if an OC makes a by-law that you believe is harsh, unconscionable or oppressive then you would need to make an application to the Tribunal to have it declared invalid.
We don’t know the test that a Tribunal might apply in such a case, but it is reasonable to assume that the Tribunal would look at the circumstances of the strata scheme as a whole, and balance the interests of all of the owners in reaching any conclusion. “Harsh, unconscionable or oppressive” are pretty extreme, compare a term such as “unreasonable”.
Importantly – the section does not mean that if an OC puts in a by-law that you don’t like, for whatever reason, that you can just ignore it, either entirely or in part. If you do that, then you are breaching the by-law. If it bothers you that much, then you can make an application to have it declared invalid, and then you would have to satisfy the Tribunal that it falls within the terms of section 139(1).
There is no legal requirement to balance the specific needs of children as distinct from any other class of resident of a strata scheme. If there were, it would be in the strata legislation. An opinion written by a legal academic, however well qualified, does not constitute a legal requirement. The interests of children resident in a strata scheme may well be considered in weighing up the interests of the owners as a whole, but that is a different matter.