Not sure about this, but I think that on the dashboard is legal. If so, you could have it in the car, throw it on the dash when you see them doing "revenue enhancement", or even while getting pulled over. I would just tell them that there is no provision on the front for it, (when I install RUF bumpers).
Any Minnesotans out there know whether front plates are required? I have MN. plates on 911 now, planned on telling cops that it is not required in MN. I see a LOT of not quite new anymore cars with NO plates at all in L.A., people get away w/ that one forever sometimes.