I think with the more Wastelanders in the Encounter, it should decrease the ease of finding it.
1. There is probably combat going on, taking place already as the secondary(or tertiary, etc.) Wastelander walks upon it.
2. The groups the Wastelander sees is sometimes 2, 3, 5+ Wastelanders camping in it right now. Be nice if..
+1 player = -5 % to see,
+2 = -10%
+3 = -20%
.... etc (with a cumulative drop in difficult as more join)
The reason for this is players mob into TB encounters near cities and wait... and really, it should be EASIER to see a mob of people out there. So instead of using the players playing any difficulty in being found, it is based entirely on the base encounter (how it is atm). All pks have to do is drive in their taxi, find the biggest/hardest encounter then camp it. Which I Have seen done. Several times. They are like the new TB Caravan traps outside NCR.
Edit: It should be raised according to Additional numbers of Bodies, as I forgot to account for Mercs/Slaves. Which I have also seen done. A lvl 21 will automatically lose if he falls into a fight with 3 players +10 merc/slaves. The swarm, with the NPCs lol-crits, generally will prevent any sort of escape.