When a family member or loved one decides to challenge a Will (or a Trust) based on "undue influence," proof is often a challenge. Undue influence in executing a Will is not usually exercised openly in the presence of others. It is usually perpetrated in secret. Changes made to a person's estate plan due to undue influence are often hidden by the perpetrator. As a result, most of the time undue influence cannot be proven directly. In many instances, it must be proven by way of presumptions and indirect or circumstantial evidence.