Related to the topic at hand, there's also no current way to do 'random encounters'. There are hordes and randomly spawned single NPCs, but nothing like a monster group that isn't attached to specific place.
I can do hack "encounters" right now by altering maptiles so that there's a 10% chance you find a parking lot with a group of hostile NPCs hanging out there. But that has the same problem where it only happens once the first time you visit a place. And once a player has seen it once, they know about it and are ready for it from then on. Not much of a curve ball.
Templates might be able to include something like a random encounter. Where it's not really altering any of the stuff on the map, but it does place a group of NPCs or a special monster group there. Encounters wouldn't need to be based on map info, like fungal activity, they could just have some really low chance of happening, and maybe a cooldown to keep them from hitting in rapid succession.
With that you could run into scavenger teams or other groups of NPCs all in one faction. Or you could have custom monster groups like a pack of robots out exterminating fungals or other weird stuff.