Ignorant

Leonel's Dream Force affinity was far too high. Even if one hadn't gained access to the Dream Plane yet, having high affinity would allow you to sense its pull even while unawares. Due to this, whoever was trying to mess with him had to be extremely subtle and couldn't just dig through his thoughts and memories as they pleased. 

Of course, you could avoid this sort of probing in other ways as well. One way was through the use of mind protecting treasures, something that was far more common in Complete Worlds. In addition, you could avoid this by just being extremely powerful yourself and having a Force within the Life State. 

Having a Life State Force made you more sensitive to the matters occurring in the Second Dimension and you could fight against them. That way, even without protective treasures, you could be immune to the probes of a Dream Force Master.