ExplanationOfBenefit resources that correspond to prior authorization could be identified (and searched for) using the `use` element set to `preauthorization`.

This would avoid having to make meta.profile required and search on profiles, and have a clear way to separate prior authorization from claim data in the resource itself.

Examples already use use = "preauthorization" 

Setting profile to make use 1..1 Must Support and setting value to "preauthorization".