If the TPMS monitor loses connection with the sensor the period of time it takes to notify you of the loss of signal can vary a tremendous amount. Some brands can take up to an hour to notify you of a lost signal. So you could be traveling for an hour with no contact with the tire/s and you wouldn't know it. And the sensor could reconnect and you'd be none the wiser.
Some brands are very quick to notify you of a lost sensor signal. It just depends on the brand. My guess is that the maker will recommend a repeater.