I like the idea!
Bear in mind that I'm not a lawyer, and things may have changed, or I might have it wrong-
@Essjay might know more just because she's smarter, lol. But, I believe that there's a loophole in the law that if you carry something with the purpose of using it as a weapon, they can still prosecute you. I could keep this in the house, no problem! But if I were carrying it in my purse while out and about and used it on someone, and said I carry it in self defence, I could be prosecuted, since I'd be carrying it for the purpose of using a weapon.
Again, I might have this wrong, and I'm drawing on memories from when I was a hot young thing in my twenties, and when looking into stuff I might be able to carry on walks in case of dog on dog attack.
That said, if I claimed to carry it because of a phobia of wasps, then it's more of a grey area. I'd also rather face a court where common sense may prevail, rather than face an attacker empty handed.
I did learn in my early twenties that a stiletto heel makes a fantastic weapon. Can pierce right though a shoe and the foot within, with just enough pressure, or do a lot of damage to a face or other sensitive areas. That's good to know, for any women out there who enjoy a night out.