Sapper is exactly right on this statement -
They forget the primary thing of any standing force is to control all lines of communication and to lock down the highways.
'The adversary' will indeed control comms. Jamming a range of frequencies, say the entire 2m and 70 cm Ham bands is trivial for those with commercial jamming equipment.
So anyone caught in a standoff situation may not have regular radio comms as a viable option. Being prepared, one would have pre-arranged 'splits' with trusted people at some distance. While the bad guys will jam your frequencies, it is very unlikely they will jam theirs. But talking on theirs is unwise, close would likely be unmonitored.
Many radios have that ability, often called 'offset' and most newer ones can adjust the offset. The Baofeng UV-5R can offset up to 10 MHz. For example one party could set receive to 154.600 and transmit to 146.600 the other end does the opposite. Other guy being, RX 146.600 and TX 154.600
Just keep directly off any used frequency, 15-20 KHz should be good to avoid interference and detection.
