Speaking as a Warranted Rapier Marshal-at-Large for the Kingdom of the East, they'll get my rapier (and main-gauche) when they pry them from my cold dead hands.

(Only half of those really belong to me and my wife.)

(I dare say the archery blunts taped to the tips and the lack of a true edge will help me out.)
First, all of these idiots running around thinking they're a ninja. We've already had someone link to a list of idiots with katanas stories.
Ah yes... That would be this link:
http://www.thearma.org/essays/Fringe.htmIt never gets old.

Based on those stories, it would seem that wall-hanger katanas do seem to attract a certain type of character, so I'm more inclined to see the law as a kind of "social profiling". OTOH, it could just be the relative cheapness and availability of that particular type of word (compared to, say, military sabre, or a Norman longsword) that inflates the percentage of crimes involving katanas.
That same site also has an interesting article on whether or not it's possible to determine what constitutes a "real" sword, as opposed to a wall-hanger. See
http://www.thearma.org/spotlight/heymr.htmWho's to say that a modern reproduction of a vintage katana is not itself a "real" katana? Does it have to have been be made in Japan? What if it was made in Japan, but had only a crappy cast metal blade? What if it was a high-quality blade forged by a recognised master bladesmith, but he made it in his shop in Singapore? Does it have to have been made a certain number of years ago? If so, would a modern blade by a Japanese master bladesmith forged for the Emperor's dress uniform not qualify?
How about a plastic katana? They've banned (or at least controlled the sale of) plastic replicas of guns.
Wasn't there also something a few months ago about the U.K. banning the sale (to
anybody) of kitchen knives with a pointy tip, longer that something like 4 or 6 inches?
Swords in the possession of youths? Well, check out this bunch of vicious thugs:

Wearing their gang colours and flashing gang signs.
Finally, a bit of Filk that touches on urban violence:
I'll See Your Six!
Ioseph of Locksley
(c) copyright 1993 W.J. Bethancourt III
TTTO: The Sleeping Scotsman
--------------------------------------------------------------------------------
A lovely lady went one night to a revel in the East
With dancing and with singing, with wine and Roasted Beast
When the revel came unto an end, she started out for home
Wrapped well in her woolen cloak, and walking all alone.
CHORUS: The things you will run into, the people that you meet
Walking all alone upon a New York City street!
Now, New York City's not a place for walking in the dark
Not in the streets and alleys and especially not the Park
But off she went most happily, without a single care
Wrapped up in her woolen cloak, all in the midnight air.
A street-tough jumped in front of her, with three friends in the night
And pulled a six-inch switchblade, that glittered in the light
He waved it underneath her nose, and said with fiendish glee:
"Give me all your money, girl, this is a robbery!"
She gazed upon the switchblade, and smiled a happy smile
Said "Boy, you ain't got any brains, and lack a sense of style!
You're standing where I want to walk, please move out of my way!"
The tough said "Girl, I'll cut you, and rob you anyway!"
All wrapped up in her woolen cloak, her garb was quite unseen
Her hands were hidden out of sight, and so was chain-mail's gleam...
She said "Now, go rob someone else, my money stays with me!"
He said, "I'll take your money with my six-inch snickersnee!"
The lady's smile got bigger, the robber took a swing
The chain-mail took the blow; the lady didn't feel a thing!
She pulled a Kirby broadsword, the robber's soul to shrive,
And grinned and said, "I'll see your six, and raise you thirty-five!"
The bandit gazed upon the sword, and then upon his knife
He turned and ran, with his three friends, a-running for his life!
Don't think a lady's easy, don't think she's helpless prey,
Especially if she is a fighter in the SCA!
Now if you don't believe my song, then ask the lady fair
With Cheshire Cat upon her shield, a blazon very rare:
Sir Trude is her name, me lads, if she should pass your way;
The very first of the Lady Knights within the SCA!
Supposedly based on a true story about Countess Sir Trude Lacklandia, but seems more to be one of those urban legends floating around in the Society, like the apocryphal
"Blood for Odin!" story.