I have an 03 Cooper S Hatchback and a 2011 Countryman S, neither have back-up cameras. Do know of blind spots and have accustomed myself to look around these spots. Noticed first when merging onto highway and did not see person that was not going to change lanes when I was merging. I, also, have a 2011 Land Rover with camera. When camera comes on it says: "Look behind before backing for safety", even with cameras you must still turn around and look.
Charlie Croker ,BRG 03 Cooper S, SCCA Solo, PDX, Time Trials, RoadRally, and Stella, 011 Oxford Grn Countryman S