You would think that when unions were negotiating pay and benefit related matters, they would avoid having hour cliffs in benefit eligibility to avoid creating the incentive to hire part time employees just below the hour cliffs.
Then they also have to consider that full benefits at a relatively low part time level (10 hours per week) will incentivize the employer to try to hire each part time employee to the highest number of hours possible, because full benefits add more per hour to the cost of a 10 hour per week employee than they do to a 30 hour per week employee.