A question for the wise: would a background count have an effect on a mundane character, and if so what would that effect most likely be? Let's take, for instance, the site of the Auschwitz I death camp (Background Count 5, maybe 4 absolute minimum). Now, just being within half a mile of it is likely to send a mage bugfrag, but what effect would being there have on his mates?

-JH.

I don't think it would have any effect at all. Certainly the rules for background count in MitS say nothing at all about mundanes noticing any effects at all. It specifically mentions that awakened characters might, even if they're not perceiving/projecting, which again really says that it's only awakened characters that have any chance of noticing anything. By the rules, even mana warps don't seem to have any effect on mundanes.

However, that being said, there is a chance that a mundane will notice a slight sensation when walking through a ward, and those are on the astral plane. But I guess that's more to do with aura intersection type stuff, in a slightly similar way to how you might notice if a spirit or projecting mage went through your aura or whatever.

A mundane can pick up on something passing through their aura (and there is training to enhance this), but a mundane can walk through Auschwitz or an astral lava flow with absolutely nothing to tip them off that something unusual is about. If a mundane in either location got as much as goosebumps or just a feeling of being watch, you could more likely lay that down to psychological tension or atmosphere than a background count.

Purely astral constructs do not affect the mundane. Background counts have no effects (game mechanics wise) on the unAwakened.

For pure story I would let mundanes have an 'odd' feeling in a place that has an extremely high background count (4-5) based on whether it's positive or negative.

I get the idea that pretty much everyone in SR has some sort of attunement to the astral realm, I mean they're all living aren't they (most of them anyway), and that means they have the force...uh...magic, flowing through them, all living things contribute to the astral, so unless you're as insensitive as a brick, 'bad places' or even 'good places' should give some mundanes a slight twinge and interact, however slightly on some level.

Have you run your fingers down the wall
And have you felt your neck skin crawl
When you're searching for the light?
Sometimes when you're scared
to take a look
At the corner of the room
You've sensed that something's
watching you