As a Psychomancer, you can faintly detect the "feel" of Psychomancy occurring. Now that's only because even Satori only laced a wide-area intermediate memory hallucination. Not that it makes it any easier, cause it makes you more "sensitive" to it in that it is more likely to affect you, at least until you built up the immunity. You know, the whole "can't stop reading everyone's mind" issue. It's going to hit Annabeth pretty hard since she just now discovered her mage blood, Halko could probably focus well enough to forget it, and Ssarak could possibly cancel it if he remembers Mei's meditation technique. 

[quote=Freeshooter92]
Even Psychomancy has its limits. I imagine a VERY strong will can do wonders.
[/quote]

The only limits to Psychomancy is one's imagination and his ability to make others see it. Even a strong will has their moments of weakness, all it takes is determination. A strong will might survive it, but that doesn't make them immune. It just makes them die a little bit slower than the others.