Police can use a mechanical boot clamped to a wheel to prevent a parking scofflaw from moving a vehicle until he pays the fine, but it’s a hassle. Boots are heavy, difficult to install and remove, and time consuming. But now meter maids have a new weapon in their arsenal: the Barnacle! This is a large “parking ticket,” so to speak, that adheres to the vehicle’s windshield and covers it completely. It sticks there by 700 pounds of suction, and is wired to tell the cops where you are if you drive off anyway. Read about the advantages of the Barnacle at Wired. Advantages to the government, that is, because it would suck to find one on your car. However, it may prove to be easier to deal with than the boot for drivers, too. -Thanks, hearsetrax!
I would also image that it would be possible to puncture the the suction skirt and remove it yourself. Slide a knife under the edge and give them a few cuts, no angle-grinder required.
Let's say windshields really don't like glue... *hum* :s
I thought it was funny, but time will spin a most curious yarn soon enough =^)