Zero tolerance laws are understandable for drivers- if you are driving a motor vehicle, cops should have the right to breathalyze you. However police officers will often breathalyze passengers too. This isn't a problem, unless you're under 21. Of course drinking alcohol underage is illegal- but everyone knows that it's common anyways.
It is unfair to breathalyze underage passengers who are only trying to make smart decisions when drinking by having a designated driver. If you are underage and breathe anything above .00, you can face criminal charges, fines, and have your license taken away. Instead, police should have the option of escorting home teenagers who are suspected of drinking, however they should not be able to breathalyze passengers.