I was out in my wife's 06 Freestyle and got a flat. I was about 20 miles from home so I put on the donut spare and went on my way. As soon as I hit 40 mph, I got the traction control light. Shortly thereafter, I heard a beep, got the brake light, abs light, the message center said "check brake system" and the speedo went to zero.
If I shut the car off, all of the lights would reset and then come on again at 40 mph. So I limped it home, threw the bad tire in the back of the truck and took it to a tire shop. Once the real tire was back on, no more issues.
I'm assuming that all of the problems were due to the fact that the smaller spare tire was spinning faster than the others so the traction control system and abs system thought something was wrong. It took me by surprise that I couldn't put the spare tire on and drive for 20 miles without the car going haywire.