I think the only way you could have gotten in trouble in the situation you describe would be to actually carrying concealed and not have a Minnesota recognized permit to carry to do so. Always keep in mind that what you can legally do, there may be one or two LEO's, CO's or Park Ranger that may not actually be aware of what is allowed under current law and that one or two will be the one you encounter.
Had a local LEO tell me that the only way I could carry a handgun was with a permit to carry. I explained to him that without a carry permit some city, county, townships may have an ordinances that would not allow open carry, but that I could carry openly without a permit walking down my rural township or county road and could be afield on both private and much of the Minnesota state land without a permit in many situations. He again stated that I could not for any reason and would most likely get ticketed if I did so. So I asked a simple question. Minnesota law allows the taking of deer with a handgun, there is a specific caliber definition in the DNR regulations when doing so. So if is legal to harvest deer under Minnesota law, how can that be done without carrying a loaded handgun on either private or state land that is open for hunting deer? The look was worth a thousand words, I could see his brain was in overdrive to analyze this. This LEO was an acquaintance, I had even done some training with him in the past, so it was a fun conversation.
He did admit that he may be not fully aware of all the aspects of carrying. At a later date when I talked to him he said he had done some research and found that in many situations a person could open carry without a permit.
But thought everyone that did carry a handgun should get a Minnesota permit to carry anyway, and yes he is pro carry.
I am not try to fault this LEO, he was just not aware of the specifics, but then again he was a metro LEO and not a rural LEO, CO or Ranger. He did take the effort to research it though and that is a good thing.