Re: covering the ravine - I seem to recall a Jeremy Clarkson article which suggested replacing safety belts and airbags in cars with a big spike in the centre of the steering wheel, thus acting as a deterrent to bad driving.
More seriously, I feel it would be better to use EMAS rather than adding more concrete to a fairly depressing area, containing as it does several major highways plus Pearson. Maybe the Government of Canada could release some of the security charges and airport rents they are grabbing from Pearson and invest in safety rather than demand it be self-financed.