HIPA
HIPA, which stands for the Hemophile Information Protection Agreement, is a loose accord among the blood dealers of Doskvol to not disclose information about their clients.
When Elmer Dink went missing, the rest of Demon Squad sought to discover his whereabouts from his blood dealer, Juul, who would not provide that information until Patch produced (forged) documents indicating the gang's authorization to know it.