Earlier this week, I was scheduled to fly DTW-YYZ-YVR. My DTW was delayed at least 4 times, it was scheduled to depart at 2:45PM and didn't get out until 9:30PM. Question is, If I would have skipped the DTW-YYZ leg and just driven to YYZ after the first delay, would my ticket me invalid. I had several friends that were driving and I had a chance to catch a ride after the first delay which would have gotten me to YYZ with plenty of time to catch a connection. Instead, I missed every alternate connection with every delay notice and of course when I finally reached YYZ, it was too late as there were no more flights to YVR and AC rebooked me to the next day and I had to stay over night in YYZ.

I know normally skipping the first leg would void your ticket but what about a case like this?