Knowing approximately where the bike is is only 1/3 of the battle. You still have to physically put your hands on it and remove it from whoever has it. I applaud the intent of a bike "lojack" but good luck getting the police to lift a finger when your bike tells you where it is.
That 50 bucks is better spent on a good U-lock upgrade.
Compared to those dramatic declines (and yes, 1993 was a pretty bad year for crime in the US, but that's the FBI's stats), motor vehicle theft has fallen off a cliff.
In 1993 there were 606 per 100,000 inhabitants. in 2012 there were 230. The new number is 38% of the old number.
I hear about fairly advanced car thefts in the UK all the time (RFID cloning, etc), but it's a problem that virtually doesn't exist anymore in the US in the eyes of car enthusiasts. (Yes, 20 year old Honda Accord parked in the ghetto is still a target. But modern vehicles in relatively good areas are simply not something we worry about anymore).
https://ucr.fbi.gov/crime-in-the-u.s/2012/crime-in-the-u.s.-...
Now it's parts. Wheels, airbags, bumpers, etc.