All fair points -- especially elbows (and knees!).

I didn't see anybody mention spitting or biting, also quite valid, and also tools/tricks that nobody can take away from you (short of knocking out teeth, I suppose).
If I could keep a Mean Chuck in my pocket I would do so; a Pocket Chuck (mini Chuck? Nun-Chuck?) would be just lovely. And ya don't always have scissors or a bottle (or a Mean Chuck) handy.
As for bangsticks, they pose more problems than knives! Not just from the legal/social standpoint, but they're bloody heavy and awkward to carry. Done all that too.
The goal here is to have a consistent tool and know what to do with it -- like guns, you're only really proficient when you know what the gun is, where the controls are, and what it does. (E.g., you don't want to be fumbling with the safety on your Glock... oh, wait, Glocks don't have manual external safeties! But why won't my 1911 shoot? Oh, shit, cock the hammer! Or flick off the safety! Muscle memory, it's all muscle memory.)
For those who haven't met me, it's not like folks usually pick fights with me -- I'm not quite MeanChuck-sized, but large and scruffy enough to discourage most would-be fuckheads from bothering me and find an easier target.
I'm really interested in having an anti-knife tool -- that's the real drive. Most folks don't carry guns, but lots of people (including many of us us) carry knives, and they're super simple to improvise (as plenty have pointed out above). Countering a knife when you ain't got one is a real fucker. Yes, I know techniques that'll theoretically do it, but a lot of them are a little on the "hopeful" side, and rely on the other guy being a total moron.
If I take RevCBL and give him a big knife, he could make even Mean Chuck's day a little awkward if he wanted. Chuck is massive enough that he could probably still drop RevCBL with his bare hands, but it's a little too likely that he'll get perforated in the process, possibly terminally. And I'm working with the grand assumption that RevCBL doesn't have any martial training and is generally a nice guy who wouldn't want to punch holes in Chuck.
It's a given that you'll get cut in a knife fight, it's just making sure that you get superficial wounds while the other guy is incapacitated (i.e., unconscious due to blood loss or incapable of retaliating due to severed tendons/muscles).
If YOU have a knife, though -- or in this case, a pointed stick -- the balance of power is a little different. Then the other guy is subject to the same hazards as you.
In MH's scenario, his belt-flail provides some range that the knives ain't got -- that's a good thing -- but having messed around with hinged weapons and whips, I know how difficult they are to manage. Wrapping one's hand in the belt as protection isn't a bad idea, but it'll limit your ability to grab stuff, and it still does little against attacks anywhere else.
Bottles, scissors, etc are all really just "other versions" of the pen -- they're improvised weapons, and they roughly fill the role of the pen here. I'm just trying to find a good, easy-to-carry improvised "tool" that serves multiple functions including a last-ditch self-defensive role.
Think improvised weapons are just "improvised"? Most every cop in America caries a
PR-24 side-handle batonthat's based on the Okinawan
tonfa, which was in turn an adapted mill-wheel handle that the Okinawans used against mainland invaders with "real" weapons (swords, spears) -- turns out they're extremely effective, which is why cops carry clones today.
Nunchukuare threshing flails that are similarly re-purposed. Same deal. Or the
Eku, which was obviously an oar.
The beauty of these items is that they really are "tools" and can't be effectively outlawed or controlled any more than screwdrivers, hatchets, or chainsaws.
And yes, Priest, the best tool is the one the other guy doesn't know you have. I'm working on the assumption that nobody here is going to pull a knife on me in anger -- otherwise I'd be packing heat to Doom, as some other folks here probably will.
Like I said, this was largely for nutjob karate-ka like yours truly, so I apologize for my over-explaination.
--Jaeger