Hmmm, could work but a problem you could have is signal and power.
Tracker systems have their own power source which lasts for months and sometimes years without a charge, just in case the battery's disconnected.
Signals self explanatory really. Depending where it's placed in the car could compromise signal as will if the cars stored somewhere over night. Thieves generally do this to see if the cars got a tracker unit fitted.
Not a bad idea tho
