Yes, any obstruction in your windshield area or rear-view mirror area is a violation of Minnesota Statute § 169.71.1(a)(2).
The exact language says, “a person shall not drive or operate any motor vehicle with any objects suspended between the driver and windshield.” The statute also prohibits cracks in a windshield which limit or obstruct proper vision, and any signs or posters on any of the windshields.
If an officer observes any violation of a traffic law, they are able to pull you over. With that being said, they are only allowed to question you as to the reason they pulled you over and would need further evidence, or reasonable suspicion, of additional illegal activity to expand the scope of their questioning. Terry v. Ohio, 392 U.S. 1 (1968). For example, law enforcement would need some evidence of alcohol use in order to ask you to participate in field-sobriety tests.