Cut and cover sounds like a grand way to save money, but based on the estimates tunneling is approximately 40% of the total cost. Are we assuming that cut and cover is 20%, 30%, 40% less expensive than tunneling? I would highly doubt that, labour was a lot cheaper when the original lines were dug cut and cover and the reality is there wasn't much of an alternative. If you think people are freaking out about the plans now, wait until someone tells them there will be a swatch of Scarborough ripped up (and likely a lot of property demolition) to build this thing. Even at a 30% savings vs tunnelling (which i doubt its anywhere near that) you are looking at a total project savings of about 10% - not much when the price goes up every report.