Scrying effects...

[onthetown]

If the subject you're trying to scry on succeeds on his/her/its Will save, do they know that somebody is trying to scry on them? The SRD says that your scrying attempt simply fails; however, in our campaign, instead of failing the person simply knows they're being scried upon and can cast Nondetection, watch what they're doing, etc, until they know that the scrying ends. I was wondering if this is a general rule or just something that my DM apparently does.

[Toliudar]

As I understand it, the will save just lets the person know that there was a metal effect that they were able to resist. However, some DM's are more specific, and add detail to that. If the DM gives the PC's that kind of information ("with a tremendous act of will, you turn back the vampire's attempt to take control of your body"), I'd say they're justified in giving the same kind of information to their NPC's as well. If that's true, maybe the person being scried can retroactively choose to "fail" the will save, and allow the scrying to happen anyway.

I'd say your DM is taking liberties...hopefully, ones that might serve the story.

[onthetown]

Ah, I don't mind the taking liberties part, I was just wondering for the specifics of the spell

[hewhosaysfish]

From the SRD:

A creature that successfully saves against a spell that has no obvious physical effects feels a hostile force or a tingle, but cannot deduce the exact nature of the attack. Likewise, if a creature’s saving throw succeeds against a targeted spell you sense that the spell has failed. You do not sense when creatures succeed on saves against effect and area spells.

[Jack_Simth]

From the SRD:

Also from The SRD

After rolling a saving throw against a spell targeted on you, determine what that spell was. No action required. No retry.

. DC is 25+spell level, so for your basic scrying spell, that's something like 28, but it's possible.

[Tehnar]

You also get a DC 20 Intelligence check if your int is higher then 13 to notice the scrying sensor.

[Lysander]

Even if they fail their spellcraft check though if they know about scrying, and they sense strange magic while there's nobody else around, I'd say they should suspect a scrying attempt as a likely candidate.