Whoa peep...be sure to read the op's posting again. He/she never said it was illegal discrimination - only discrimination, which is in fact possible, and as many of you have pointed out, is legal.

The advice I would give is when it is time to resign, consider a 4 week notice and be pleasant. Ask the company to waive/forget the tuition. Many companies do just want you mention but circumstances vary greatly. Going after $2k is different that $15k. Usually it depends on if they feel they got a fair shake from the employee.

I once had a co-worker put in his resignation a month in advance (tuition reimbursement was pro rated at the beginning of the year). He owed $15k if he left in December, $10k if in January. A week after he submitted his 4 week resignation, his boss (they didn't get along) told him to pack up his stuff and leave and that he was accepting his resignation immediately. Pay stopped right away, benefits at end of month. My coworker informed them that he felt this was company termination which meant no obligation to paying back the tuition and also allowed him to severance. Company disagree, coworker got lawyer, back and forth, they agreed to drop demand for tuition if he agreed to drop demand for severance.