And every cop has the right to punish you for it. Not a real legal right of course, but one forged through generations of corruption, insecurity, and abuse of power!
In Germany, you'd get a citation and a fine. In the US you roll the dice on a beating, a night or two in jail, and/or a thought-up charge as retaliation.
http://dejure.org/gesetze/StGB/185.html - http://dejure.org/gesetze/StPO/374.html - http://dejure.org/gesetze/StGB/77a.html