DISCLAIMER: I have no financial or other interest other than curiosity in any products mentioned.

There have been several threads regarding pack theft at shelters and elsewhere. I've also been to stores where backpacks are not allowed inside (usually near schools). So I began thinking about rigging my pack with an alarm. Of course someone has beaten me to it.

Here is one: http://www.dobermanproducts.com/products/se_0304.html
There are other similar products, some called door alarms or hotel door alarms.

It looks like it could be easily rigged with a cord tied to a secure object if it weren't sensitive enough to motion.

Has anyone ever tried anything like this? Is theft a serious enough problem?

I imagine it could also be useful for bear canisters, especially if it had a flashing light to go with the siren.