I gave your idea some thought for a 2500 mile roadtrip that I did through the Canadian maritime provinces this summer. I eventually decided that the risk was low, and that I would rather have the luggage and cooler space than a spare tire.
Crossing New Brunswick, with the only BMW dealer in the province about 80 miles behind me, and the only BMW dealer in Nova Scotia about 80 miles ahead of me, I ran over some unavoidable metal road debris. I had a nervous few hours, waiting to see if the TPMS would trip, but the tire wasn't damaged, and I'm still driving on it.
For me, Plan A was to trust the tires. If I didn't trust them then why hadn't I already replaced them?
Plan B was to use the Google to find the closest Canadian Tire dealer, and just buy a pair of whatever they had. Plan B wasn't needed.
In a real emergency, Plan C is a plug kit, which I know how to use, and a small compressor. Some prefer a can of Slime, but I expect that you might need to replace the TPMS on that wheel afterwards.
Last edited by 02420X3; 12-05-2012 at 11:20 PM.