Warfare, be it foreign or domestic, is changing. The modern battlefield is saturated with sensors of all types from drones to night vision to electronic warfare. As this technology becomes more and more available/affordable to civilians, even irregular warfare is evolving. In order to survive the ever-changing nature of war, we must adapt along with it.
Particularly impactful is the common availability of thermal optics. Thermal optics, which read heat signatures, are incredibly potent tools. Although somewhat cost-prohibitive, they are no longer as unobtainable as they once were and can be had for under $2000 in some cases. It is safe to assume that any large-scale civil conflict will see at least some use of thermal optics on both sides, so we must be prepared for this reality.
In order to learn how to deal with a thermal-equipped enemy, we must first understand the technology we are dealing with.