I know that in Ontario the reason that you "technically" can't use
heating oil is that there is no road tax included in the price and that's why it's cheaper. We call that "coloured" fuel here because it is dyed pink. But we use it in any "off road" vehicles eg. bobcats, tractors, diesel mowers etc. The MTO (ministry of transportation) has been known to "dip" tanks in diesel vehicles to see if it's coloured or not, if so there is a BIG fine.