This exact situation happened to me. Remember you will get a TPMS warning if you have a slow leak so there is no risk of damaging the RF tire unknowingly. I added some air using my car battery powered pump and drove to the dealer where they discovered a big bolt in one of the rear tires. It took two days to fix it. I added air one more time as a precaution since I was driving the car in the mean time. Before this experience, I was a bit uneasy with the RFT choice but now I am very comfortable with it. I can't think of a situation where I would prefer one of those dinky spares. A better option might be to carry around an unmounted full-size tire. The disadvantages of that are obvious.