I can see people still driving with this on their car. They get home and all their homies laugh about it. They then decide to find some way to break it off, and yes, they will find a way. Heck, just drill a small hole from inside to release the suction. Or replace the windshield (Hmm, $150 for a windshield or hundreds in parking fines).
Then you have to worry about windshield damage. I have a small crack in my windshield, you put this giant suction machine on it and now I have a crack all the way across my windshield, you caused it, you need to pay for it.
Then there is to problem of returning it. You expect somebody that does not want to pay for their tickets to drive somewhere and drop this thing off? They will keep it, cancel the credit card they paid with so the device can't be charged to it.
I still think the boot is a more effective device, but agree it is harder to put on and you have to have somebody come out to remove it before the car can be moved.
I do know some areas have crazy parking signage and rules, so you may not even know your illegally parked, but still, pay your tickets and you don't have to worry about this thing or a boot.