What does this spell do? If you are trying to find out if the third person is a caster or not by using a magic, you cannot do that.
The magic is attempting to probe the guy's mind to see if he's a mage. Given that it's low-effect casting, and spontaneous at that and thus
very subject to change, I doubt it will be successful, but Garath's an arrogant kind of guy.
I figure a level 4, maybe only 3 effect would be able to search someone's mind enough to see if they are actually a spellcaster with some degree of certainty, but level 2? Doubt it.