As to the issue of searching vehicles in company parking lots or garages, it depends on your employment contract. The general laws - and Constitutional protection - against illegal search / probable cause are to protect us from the government and do NOT apply to private citizens on private property. If you come onto my property you will be subject to whatever rules I say (limited by criminal law). And you'll find that many companies, either in the employment contract or the employee handbook (which is usually adopted as part of the employment terms) there is broad permission given by the employee to the employer to do things such as searching personal property located on or in company property (your car in their lot).