Can a provider leave it up to an individual who controls content to determine if his/her financial relationship is relevant and needs to be mitigated?

No.  With the new Standards, the ACCME now requires that all financial relationships with ineligible companies be disclosed, and clearly outlines that it is the responsibility of the accredited provider to determine relevance based on what has been disclosed and the topic area being addressed by the accredited CE activity.  The responsibility for identifying relevant financial relationships cannot be delegated to the person disclosing a financial relationship.