A friend of mine is a lifelong Colorado resident currently studying at the University of Minnesota. Until now, she has maintained her voter registration at her family home in Colorado and voted absentee. She is strongly invested in local and state politics and cares more about having a voice in her home community than the place she currently attends school. She has a Colorado driver's license and receives most of her important mail at her address in Colorado, but spends the majority of her time in Minnesota.
This friend will be unable to participate in Colorado's presidential caucus, which has no mechanism for absentee voting. She could participate in Minnesota's caucus, which allows same-day registration and for which she certainly meets the requirements. However, she is concerned that doing so would force her to give up her registration in Colorado until she moves back permanently, which will not happen for at least a year and a half.
The question is, is it legal for her to register in Minnesota, participate in a caucus in March, and then switch her registration back to her parent's house in Colorado to vote in the next election there in November? That plan certainly seems shady, but her intention is simply to vote in every election, not to game the system or commit fraud. I suppose that if she were permanently relocating between the primary and general this wouldn't be a problem- does the fuzzy resident status associated with being a student change that?