I think most of you haven't spent much time in super bad climates. If you are say leaving from work, and you just got hit with an ice storm that leaves your car so frozen that it takes even 20 minutes to open the door...who has time to wait 30 minutes for the defroster to do the job? Hell, getting to a point where you can push it off is hard as hell cause it's thicker near where the windshield meets the metal.
Plus you usually only have your ice scraper and nothing else. If veggie oil really does work that would be cool cause you can keep that in your trunk. I wouldn't mind hearing about this. Just helped a 33 yr old friend by telling her about using cat litter under the tires for traction that she never heard about before. so you can always learn new stuff!
Getting the car running and the defroster on high is a definite. Plus, getting to a point where you can rip big chunks off..a major bonus. Now, how do you get to that point? Even with super thick scrapers you can still break them jabbing at the ice. I always kept de-icer in my trunk and used a bunch near the bottom of the window where the heater air makes it's first contact with the window. Then proceed from there.
lastly, I took the option of moving to a climate where I don't have to worry about cleaning inches of ice off my car.