Explanation:
If you bring a runaway slave into your home and don't report it, the head of the household will be put to death. I'm guessing that during the time, kidnapping people for more labor work to be done was illegal, especially when it was done without permission by The Public Proclomation of the Major Domus.
The Way Society Changed:
Before the law was passed, this would be done constantly to keep possessions they didn't want to trade or to save currency (whatever currency was at the time). After it was passed, people had to start notifying the PPMD about the enslavements so their heads won't get hacked off.
Hope this helps!