Last September, 32-year-old Arielle Townsend came home to a letter from the federal immigration department stating her Canadian citizenship was at risk of being revoked. Townsend, who lives in Ajax, Ont., was "completely blindsided." She'd come to Canada as an infant in 1992. She was not yet a year old when a Mississauga, Ont., citizenship office issued her a citizen card."I was shocked and completely in disbelief," she said. "It's almost like you go to bed as one person, and then you wake up an