I had a similar experience with Discount Tires (aka America Tire Store) when I had a low tire pressure indication on my toad's built in TPMS while driving it around town. Pulled into a Discount Tire Store but since it was at closing time and they had locked up, one of the guys that was just leaving, stayed and pulled the tire off and put on my spare and told me to come back first thing in the morning to get the tire fixed. Returned the next day and it was determined that there was no leak in the tire so we assumed that the aftermarket TPMS (that I have for both the MH and toad) sensor was not on tight. Refiled the tire and put the sensor back and reinstalled back on the car. No leaks.
Went in to pay... guy at the counter said no charge, have a nice day.
Ron
ps... Gary, You really need to get a good TPMS. If you had one, you probably could have saved that tire.