All righty. That's what I'll do - ride the thing home and replace the tube when I get there. I have lots of tubes at home, but I just carry a patch kit when I'm commuting - part of the Stuff Being Carried Around Reduction Program I've enrolled myself in.
Thanks for the advice. If, by tomorrow, I have an amusing story about a flat tire on a busy highway overpass, I'll most certainly come here to share it, and we can laugh, laugh, laugh.