However, the constitutionality of admitting refusal evidence depends upon whether the defendant's refusal was an adequately informed one. Wisconsin has held that informing a defendant that he may lose his driving privileges by refusing a test is sufficient to satisfy both the U.S. and Wisconsin due process clauses. But, the holding in Crandall was based on the assumption that there is no statutory right to refuse a blood test. Therefore, we conclude that the admission of the tainted refusal evidence at Schirmang's trial was error. Our analysis does not end there, however.
Evidentiary errors are subject to a harmless error analysis.
Generally, an error is harmless if there is no reasonable possibility that it contributed to the conviction. The burden of proof is on the beneficiary of the error to establish that the error was not prejudicial. At trial, Officer Alsaker and Officer Baltzer were the only witnesses. Both officers were at the scene of the stop and both were with Schirmang at the Sun Prairie police station after his arrest. They observed him for approximately one hour and twenty minutes.