being a installer of alarms for over 13 years usually the thief returns to the sceen of the crime. most of the time its some one who knows you. when you drive your car you have to be aware of the surroundings especially where you live.dont be blasting your system and not expect some one to wonder whats in your car. by the way alarms help too because most will have some type of paging system . but dont be cheap on buying one from ebay . get a good brand and protect your investment. the factory alarm can only do so much , even tho its good for all points of entry but if you dont hear it then you don't know. when you say blue light what do you mean????