It was not the text of some laws. It was engineering standards incorporated into certain building codes. The laws were like: "buildings shall follow ASME x.y.z" (to use a software analogy, it would be like requiring something to conform to POSIX, a standard the text of which is not freely published).

Eh.

Here is a freely published copy of the POSIX standard:

http://pubs.opengroup.org/onlinepubs/9699919799/

Regarding the "text of some laws", there was actually a story on HN about the city of the District of Columbia asserting copyright to their laws and making it only available via a private company:

http://www.washingtontimes.com/news/2013/mar/31/ignorance-of...

https://news.ycombinator.com/item?id=5251797

Is this distinction interesting in some way I'm missing? If the engineering standards are mandated by law, they are effectively law themselves, so I would assert that "the text of some laws was restricted by copyright" holds. Referring to external standards was the mechanism in the cases I was thinking of, to be sure.