I used to own an 8x8 Argo with Super tracks (18" wide IIRC). It would go just about anywhere.
BUT...............
When I bogged it in about 18 inches of slush, it was ugly............
If you are running a wheeled Argo and you drop through the ice, you will probably NOT be able to get out forwards or backwards. It sits bow-low in the water and so you would think that the rear tires should be able to pull you up backwards. Not in my own experience......... But you are probably OK if just one side drops through, you can generally get enough purchase with the opposite wheels to back you out.
Anyways, Argo makes a heck of a good machine, and like everything else in life has its good points and bad. You are not likely drown if your Argo goes through the ice. But you might die of hypothermia.........
Doug