Necessity of a spare?

We had one poster on this forum that had a flat just outside of Tampa, Fl on a holiday weekend. He had no spare and it only took him about 8 hours to finally get a replacement tire while he and his family sat at the side of the interstate highway. I remember him asking for assistance on this board. Having a credit card was nice, but you first have to have someplace to spend it, that can supply a tire. ERS can always send someone out to mount an unmounted spare.
When it comes to flat tires, Murphy's Law dictates that they will happen at the worst possible time.