Well here's the concern I have regarding the "can of glue", and please correct me if I'm wrong.
When one of these tires go flat/bad you probably wont notice it until it is completely flat. (because of the rim/tire size) When a tire is -completely- flat and deformed from the weight of the car, doesn't it lose it's seal against the rim? If that's the case, then you wont be able to inflate it unless it was at least jacked up.
I guess I'm also still a little paranoid from a bad experience I had back when I was driving a Lebaron convertible. I got a batch of bad tires, and one of them literally came apart while I was driving 80 down I-10. Scared the H3LL out of me and jacked up the side of my car pretty good. (the tire was only a few weeks old, and everything was at the right pressure) If it wasn't for my spare I wouldn't have been able to limp home and hour away.