User blog comment:Lord Loss/Monster Hunter Theory... Blog/@comment-4502434-20120605203050/@comment-3568461-20120606013550

They check the monster's power level with a scouter. If the monster's power lvl is over 9000, they will label it as higher rank.

To keep the monsters from interfering in the hunt, they set boundaries of the map using raviente's smell/ hormone/ urine or watever.