Q. Yesterday I received an alert for Detroit-Istanbul and noticed that the flight connects in Toronto. Would it be possible for me to book this fare, but skip the Detroit portion of the flight, and just check-in at Toronto YYZ instead. It's much cheaper than flying straight from Toronto to Istanbul.
A. Nope. If you don't check in for your flight at the departure city, the airline will consider you a no-show, cancel your reservation, and you'd forfeit the whole fare. If you do decide to book this trip, flying from Detroit, there's nothing to really stop you from hopping off in Toronto on the return portion of the ticket, though airlines frown on that kind of a thing (throwaway ticketing it's called), and of course you'd have to carry on all your bags. Though if you were looking to earn miles on this trip, there's the chance you may find your mileage account closed out as penalty for pulling such a stunt.