Are these devices even technically legal to operate in the USA? I thought 433mhz was reserved for exactly what you say - tags for shipping containers. If you use a LoRa devices in the USA I think you are supposed to be >~850mhz.
The stock firmware has region-locked frequencies, so you can't transmit on frequencies illegal for your region. There is custom firmware that removes that limitation however.
In the US, at least the 433 and 915 MHz, and of course 2.4 GHz, bands are unlicensed and widely used by all sorts of commercial, industrial, and DIY electronics. All my wireless temperature sensors in my house are on the 433 MHz band, my natural gas meter speaks (ERT) on 915...
