My friend and I live in Minnesota, are aged 20 and 19 and were walking home after drinking some beers (no liquor) at a friends house. Neither one of us were acting abnormal, loud, or giving off any signs of "drunkness". We had no possession of alcohol on us either. However, a police car saw us walking along the sidewalk, immediately asked for our licenses and gave us breathalyzer tests. We blew a .05 and .15 and were ticketed for under age consumption. I was told that a police officer needs probable cause to administer a breath test otherwise the charge could be withdrawn. Is this true and could it be argued so for my situation? Lastly, the officer mentioned later that he could "smell it" which I find very hard to believe, but is that all the probable cause law enforcement needs? Thanks for any help you can offer.