If anyone wants to know a good reason why programming trunked radios as receive only is considered to be such a serious matter, it's because of people doing silly crap like this:

And selling these radios to the unsuspecting public on eBay, for use as scanners.
As you can see, this radio certainly isn't programmed as "Receive only on the GRN" (Government Radio Network, my state's SZ OL system.)