I'm an avid cyclist, but I wouldn't touch this lock.
Here's what I would use: http://www.lfgss.com/thread17938.html
And sure, this one is lighter, but stopping my bike being stolen is far more important to me than how much it weighs.
The goal of locking your bike is to ensure bits don't go missing. However, what you're really trying to do is protect your investment. Locks stop bits going missing, but they don't protect the investment. My bicycle was locked overnight at Bristol Temple Meads train station (which I wrongly assumed was a secure-ish location). The thieves didn't manage to break the lock, so instead they just vandalized the bike so that I couldn't use it either. I sort of wish the lock had just given way, at least that way the bike might have provided some value to someone, somewhere.
Anything less than encasing the whole bike + lock + secure post in a steel case (like a bike locker) won't ensure that your bike will stay in tact.
Reusable joining link? No tools required. As to the point of doing it, well, I had the QR skewers stolen off my bike once. Stealing a chain makes at least as much sense.
They have a Pitlock solution, but it works for everything from Saddle down to chain rings. With 1 key doing the whole bike.
Not a whole lot you can do about a very motivated thief.
Most chains (even the big looking ones) can be cracked in under a minute: http://www.youtube.com/watch?v=VC3hFr8p2ck
Perhaps they'd honed a technique for cutting down parking meters quickly? I also wouldn't rule out the thieves being stupid.
I can just see a thief looking at the vespa, the chain, the parking meter and thinking 'It's a crime anyways, may as well get the 15$ in change'.
Light but tough locks are worthless, they're just going to make your bike get thrashed. You want a lock that says "don't even bother trying".
Bingo. For around town, your best bet is a an old, anonymous looking city bike. Faded paint and maybe even a bit if rust can be plusses. No gearing is a plus too (I don't mean fixed gear bikes though). Many of the fancy locks listed in the guy's comment above cost more than my town bike itself.
I lock my (very expensive) bikes out on the street fairly often, though never overnight. I only ever use 1 lock and a component protection system.
I use the Kryptonite New York Fahgettaboudit it secure the frame to some fixed street object of equal strength (newish iron railings are good, otherwise some London lamp-posts will fill this lock so perfectly that there's no leftover space for a leverage tool).
https://www.kryptonitelock.com/OutletProducts/Products/Produ...
I pair that with Pitlock to protect the wheels, though will be moving to Atomic 22 when that system is fully released.
And my saddle is secured by a chain that goes through the rails and chain stays.
Anyway, it's a cool idea, but I have to agree I wouldn't trust it without some evidence of its abilities to withstand modern bike thieves with power tools.