This has been implemented in Madison, WI and is supposedly effective.

http://www.uwpd.wisc.edu/crime-prevention-bait-bike-program....

I now have napkin designs of just this.

I got hit by what seems to be some kind of paradox: old casual bikes are targeted more often than expensive flashy ones.

For a reason I can't reply to you brk but I used the same ideas.

My last question was about communicating openly or not about it.

    - Openly would make robber aware and probably come up with attacks 
      or blocking means, but that would surely render their activities 
      a lot more complicated. Could be mass-produced.

    - Secretly a few people would have it and use it as bait, and 
      authorities being aware of the scheme would casually catch robbers 
      later. No mass-production

Oh one more thing, I was thinking about using a cellular module with custom firmware to reply to text messages with gps position but I'm not sure it's feasible.

Sometimes I don't see a reply link on certain comments; clicking on the direct link for those comments, though, shows me the "reply" button.

I tried that, without success. It's probably a karma related behavior

Actually, it's time-related and everyone sees it. Deeper comment threads have a timer that prevents comments for several minutes. It's to give people arguing with each other time to cool off.

Are those rules written somewhere ? I like the tree pruning effect of this one

http://ycombinator.com/newsfaq.html has some of them, but not nearly all of them.

The cellular+GPS is a commercial product:

http://www.spybike-gps.com/products-gps-localization/top-cap...

Me too. Especially of it were a factory installed option. You could probably encapsulate the electronics in one of the frame tubes, which would mean it would be welded in to the bike. Impossible to detect casually, and nearly impossible to easily defeat without destroying the bike itself.

Given the ratio of hours ridden to power draw of a small tattletale device, you could probably put a couple of magnets on the crank assembly (inside the tube the connects the crank to the frame), along with a couple hundred coils of wire and create a very nice charging circuit. It might take even 100 hours of riding to build up an initial charge, but I'm guessing that would be no problem in a typical scenario, even if it took 2 weeks to get there.

Isn't this something that would be trivially bypassed by passing a big spark through the frame? Burn out all electronics, without harming the rest of the bike.

Most likely not.

First, how you are going to pass a "big spark" through the frame? Carry around a big ass battery while you're on the hunt for bikes?

Secondly, the current would follow the path of least resistance, through the frame itself. Unlikely to really affect a module inside the frame, especially if that module is wrapped in an insulator.

Good point, but how much current would it require ? wouldn't this be too big to carry noisy and even smelly ?

Metal tubes make a nice Faraday cage.

Agreed. I would fund this on Kickstarter, such stings should be positive externalities in the metro they are set up in. I wonder if there have been any sting initiatives on Kickstarter thus far and what laws would allow for (it's been done before, to catch a predator, anyone?)

Outside Magazine had a story about doing just that: http://www.outsideonline.com/outdoor-adventure/biking/Who-Pi...