Seppuku

I was out with some freinds at some ice cream place and we were sittin out in the back of a truck eating icecream and talking. well after we have been there about an hour a worker comes out and tells us some one called the cops on us and they were on there way. When i heard this i kind of freaked a little becaus i had been drinkin that morning and im underage and didnt know if it would be noticable(i had a lot).Well the others decided to wait for the cop and i was stuck there with them praying the cop didnt notice the alchohol. After sittin around a half hour the we decided to leave we started to get in the cars and the cop pulls up. The cop walked up to the building talked to the people in there and left not one word said to us .Aparently they thought we were suspicous. As we were leaving the cop followed us a little but then turned off. after the cop was gone we did a little racing and went home. The thing i dont understand is how can you be suspicous if your sitting in the back of a truck in the parking lot of a icecream place eating icecream!(but earlier before everyone showed up we were sitting in the car playing slipknot really loud maybe that did it?)