Yes, if you bring more than 7 grams or 10 doses of any controlled substance into Minnesota. Even though such substances are illegal, you still have to put a tax stamp on each package or container used to transport the substance.
There's no guarantee you won't be prosecuted if you pay taxes on marijuana or controlled substances. However, information in Minnesota Department of Revenue tax reports or returns can't be used against you in a criminal court proceeding unless someone else obtains the information independently. The information CAN be used in a criminal court proceeding if it involves taxes you owe under the statute.