[MarkEHansen]

Really? What's the reason for most blow-outs? Low pressure causes excessive heat resulting in a blow out. The system I use (EEZTire) has immediate alerts for leaking pressure (among other things). These systems are pretty smart these days.

Even if you have a failure of the tire that no system can warn of, you'll still know the instant the event occurs - something not always possible on trailer tires without such a system.

I wouldn't want to be on the road without some type of TPMS - the risk is just too high.