Mercule said:
As long as you're willing to apply the same argument to Spot/Hide, I've got no problem with that answer. If, on the other hand, you do give six rolls everytime there's an NPC in the shadows, you're not being consistant, IMO.
I rarely give six rolls to six PCs. I often roll for the closest few PCs (or sometimes to the closest PC with a few other PCs rolling aid skill for synergy bonuses for the closest one), not every one in the group. And often, I do not even bother to roll if the PCs are just relaxing somewhere or the NPC is well hidden and the PCs are busy with something else.
I think the concept of:
"Hark! I see a single eye peering at us through those tree leaves 80 feet away."
to be a bit ludicrous. Given the proper concealment, hiding should be a piece of cake. Given the lack of proper concealment, spotting should be a piece of cake. It shouldn't be the 50 / 50 chance that +15 to Spot versus +15 to Hide generally gives.
Mercule said:
There are high-level Rangers (for example) that are so keenly aware of their surroundings that it's almost absurd to try to sneak up on them. It's practically a cliche to see a hero who is so alert as to be aware of everything around them even while sleeping.
Let me turn this around and use your own statement:
As long as you're willing to apply the same argument to every barmaid and every customer in the Inn looking at the Ranger. Or, every person on the street, even ones who are half a block behind the Ranger and step out a doorway, shortly after he has walked down the street.
Do you tell the player of the PC Ranger in the group about every single item and creature and thing he notices every single minute of every single day? Or, do you blow off every single detail (even the guy hiding in shadows in the alleyway) unless he tells you he is trying to be careful spotting things or he is in a situation where he is alerted?
There should be a difference between the Ranger just strolling down the street and the Ranger walking down the street peering down every alleyway, looking up at the tops of every building, glancing at the weapon hand of every passing NPC, often glancing behind him for people following, etc.
And that is a difference in alertness level that the NPCs should be able to notice as well. If he is alert and being careful and looking in all directions for signs of danger, NPCs should be able to see that. If he is just walking down the street talking to a friend and not paying that much attention to his surroundings, NPCs should see that as well.
Now, you could just handle this with maybe a difference in Hide DC, but it still is not worth a roll every single time and a roll for every single PC every single time. The situation should dictate as well. Ditto for Bluff / Sense Motive.