The Church of Light does not advocate that anyone shall become a medium.
Just because they're dead doesn't make them smart....or wise!
"When employing Mediumship and the Feeling ESP method, which are commonly referred to as channeling, one must be aware that whoever is being contacted is really no different from anyone you may meet in your everyday interactions. They key here is vibratory rate - yours and theirs. Vibratory rate (See Course 1, Laws of Occultism and Course 2, Astrological Signatures) determines the level of person and information you are able to contact. You may in the best of places, which is good. However, you may want to consider that anyone hanging around the lower to mid astral levels, may not be a great deal wiser than You! Most of us aren't experienced enough to know where we are."
Excerpt from Course 21 Personal Alchemy
That which distinguishes mediumship is the partial or complete control of the medium by some intelligence other than his own. Mankind owes a deep debt of gratitude to spiritualistic mediums. I shall be the last to criticize them. Many in the ranks of spiritualism have sacrificed tremendously that the race might advance; many mediums have been martyrs to the cause of demonstrating human survival beyond the grave. But in spite of this debt of gratitude, the very real dangers to those who develop such mediumship cause us to discourage our students from attempting to become mediums. The reason is set forth in detail in Brotherhood of Light Course 1, Laws of Occultism, published in 1919.
The subsequent years, in which through the many psychics contacted in connection with Church of Light work there has been unusual opportunity to observe the effects of the various types of development and psychic practice among a great many individuals, has but served more and more to confirm the attitude then taken. To sum this attitude up, The Church of Light does not advocate that anyone shall become a medium.