I believe you will find that this law was instigated politically by poultry farmers in california in the early part of the last century since they were concerned that ferrets on the loose would go after their livelihood. I agree that it makes little sense in this day and age, but if you do get one in the future, there are veterinarians in the state who will treat them without turning you into the authorities and ferrets make simply wonderful pets!
I have two ferrets, and I live in AZ where they are legal. I know alot about them and did plenty of homework before I bought them for pets. They have been domesticated way before cats and dogs ever were. Most people dont know that. An escaped ferret would not live long before it would die of starvation or thirst, they are not an animal that can live long on their own. Leave it to politicians to be ignorant. Most ferrets are fixed anyhow. Even if a sexually intact ferret did escape what are the chances they would come across another sexually intact ferret of the opposite sex? Not very likely imo. There are wild black footed ferrets living in North AZ, Wyoming, and S. Dakota as far as I know they do not cause problems with live stock. They mostly eat small animals like prairie dogs and mice.
i can only speak from experience here in the uk, but here people do turn ferrets out into the wild and they manage just fine and dandy, but we also have a bazzillion rabbits! we also have wild polecats (ie what ferrets were domesticated from) and they will interbreed and produce viable offspring. if ferrets are able to interbreed with the native black footed ferret, i could understand the ban, as the population would slowly become a hybrid rather than the pure black footed ferret which can spell disaster for an endangered species. unforunately these laws are brought about because of the minority, i know most people would spay/castrate their ferrety friends, but whilst there are the few who will abandon theirs in the wild, which they do because they are selfish and dont give their so called pets a second though when they dont want them any more, then these laws will always remain. which is kind of pointless in my eyes, cause the type of person willing to dump their pet in the wild aint going to care if its leagal or not, or indeed if it was leagal to own that species in the 1st place. thats why these kind of laws dont work. grrrr!
I knew someone that had a ferret and they started feeding it raw meat and they said it got mean and started to bite them, so they let it lose on their property at 8000 ft in he Rocky Mountains of Colorado. It survived on its own just fine; I would see it around once in a while. I have seen 3 different ferrets living in the wild that were from domestic. Once I saw one and it was half tame so I put out my hand and it came up to me and I went to touch it and it bit my finger, IT HURT.. My guess is they were living off of mice, all the places I saw them it was places that had a good amount of mice. A lot of things are illegal in California… It doesn’t surprise me.