I had a couple of Cummings ancestors, David and William, and their sister Sarah (Sallie) Cummings Sutherland (wife of Silas) living in Ontario during the War of 1812. They had gone there from Dutchess County NY in about 1803, but David and family were back across the border in Niagara County NY by 1829, and David and William were later in Indiana (1840) and David in Michigan. Another sibling, Major Cummins was on the Niagara frontier and subsequently also in Indiana. I expect they were not Militia members, though.