I’m a ham too, and I think a larger rig with a waterfall display would be helpful. Some, if not most of the transmissions will likely be short, and a scanner might not be quick enough to catch them. They’ve obviously programmed their Beofangs, so once you see a frequency active on the display, you can do the same.
I have 3 scanners I can use, you could setup one to do 2m, another 70cm and another for FRS, MURS, etc....
I have a Uniden SDS 100 that can pickup P25 Trunked groups and digital, etc.....
Plus I have a couple of the Baofengs and a Yaesu Handheld that can be setup as scanners....
But you are right something with a waterfall of entire range would allow you to see activity and move right in on it..
Maybe a scanner can’t catch them, but for the military, or NSA, it’s Childs play. The US government is allowing that. I.e., the deep state