"What-if you have a flat?"
We personally don't travel far without the spare. Just around town to Target or Home Depot to pickup a large item for example.
We wouldn't change the tire ourselves anyway (I have back problems). That's why we have roadside assistance.
The one time we needed roadside assistance was for a RFT complete failure. Tire failed after just 10 miles at 50 MPH after TPMS warning. Had to be towed to the BMW dealership. Since there was low tread on the tire there was no warranty on the run-flat failing, After they quoted us an outrageous price for a replacement we decided to go to America's Tire for non-RFTs (spare from BavAuto) and never looked back. The RFTs can still put you at risk.