I am not sure, but I seem to recal that in ArM5, Intellego magics and scrying needs to penetrate. Am I correct? I know in 4th this was not required, but a low casting total indicated that the subject was aware of the scrying.
A creature (or mage) with any MR that is not penetrated (and some who are!) feels "something" - they might not know what hit them, but they know something came knockin'.
In AM5, everything needs to penetrate a target's MR. Note that InIm reveals species, so there is no target with MR. That is, an Intellego spell that lets me see at a distance does not need to Penetrate the MR of the people I see. InMe, of course, does.
I suspect if you tried to InIm through an Arcane Connection to someone you'd still have to penetrate their MR, but yeah, if you used InIm on their surroundings there shouldn't be anything for them to sense (you might still have to penetrate Aegis, but nobody feels anything if stuff pings off that.)
Indeed, because the Target is Arc.
Sorry for reviving this old thread.
I would like to add that with a spell like The ear for distant voices or Summoning the distant image neither the arcane connection nor the resisting magus are the target of the spell but the room is. Their descriptions include
You must have an Arcane Connection with the place or with a person there.
I would argue that this is a strong indication, that no magic resistance will hinder the species to be sensed by the caster, nor will the scrying be noticed unless something like The invisible eye revealed is being used.
For an explicit ruling, take a look at HP p.84 Fingers for Eyes (R: Touch, D: Diameter, T: Room): "This spell must penetrate in odrer to sense creatures with Magic Resistance."
Mmh, but that is merely one example, isn't it? The core spells don't talk about resistance at all. With
Intéllego spells can be resisted but not always countered. If an Intéllego spell gives the caster a vision of the target without probing the target’s person in some way, the target’s successful resistance lets him know that he is the subject of some type of detection magic.
from fourth edition, I would expect fifth edition to explicitly state the opposite, iff the authors intended to change this aspect of magic resistance.
I know this argument is very meta, but still...
There are other examples, like: MoH p.30 Spy the Approaching Grog (R: Touch, D: Conc, T: Room): "Ths spell is designed to be cast forcelessly, as to not accidentally scry on another magus."
Indeed, scrying on other magi (HoH:TL p.52) can turn out to be a High Crime, so we also have quite explicitly there "When using scrying spells in mundane society, magi usually cast without Penetration (see Forceless Casting insert). In this way even if a magus is accidentally caught within a target, his privacy is usually protected." This is followed by exceptions, if a Redcap without Magic Resistance was scryed upon.
Also ArM5 p.113f: "Magical Senses must penetrate Magic Resistances of creatures sensed, ..."
If every change to 4th edition would have been flagged in the 5th, the needed pages for this only in the ArM5 core book would have smothered the new edition already before sending the first book to print.
In the olden times, this was being discussed by Ars Magica 5th edition authors, e. g. here.