Discretion producing unfairness without compensating benefit should be abolished outright.

Evidence

Where workers’ discretion leads to unfair and unequal treatment of clients, with no compensating benefits, it should be desirable to reform systems by removing this unredeemed source of unfairness. If, for example, a teacher’s right to strike pupils is judged to be undesirable in all cases, it is obviously appropriate to prohibit flatly this option. — Michael Lipsky, Street-Level Bureaucracy, 1418

Categorization

• XREF: Directly parallels your working hypothesis: discretion as the mechanism by which differential treatment becomes routine rather than a deviation from policy.