Because there is no message system currently, so rejecting a spell does not tell the inventor anything:
Skim Thoughts - like the other mind/perceive spell, I'll reject this one because the target should be 2 - you are reading the thoughts of a human, not of his head. That's a modern/mechanical thought, in a holistic/magical view, thoughts aren't located in the head, they are the property of the whole being.
With a target of 1, you could read the "thoughts" or emotions of a small animal.
