According to Widgets, employees have been instructed to fully use the policy to essentially eliminate IDB.
A great, positive move by Delta to meet the spirit and letter of 14 CFR Part 250 - OVERSALES
§ 250.2a Policy regarding denied boarding.
In the event of an oversold flight, every carrier shall ensure that the smallest practicable number of persons holding confirmed reserved space on that flight are denied boarding involuntarily.