I'm not fond of laws like that. *sigh*
I can see the point if the animals weren't properly cared for, but for people who do give them proper care & attention, then I don't see the problem with having more than the specified number.
The city I live in(well, not actually in, we're just outside city limits) has a 4 pet limit. Though its not really inforced. I know someone who had over 10 dogs right in the middle of the city(they bred them), and all they ever got was a talk with the AC guy, but nothing was ever done.