Every year American families lose close to 100-200 dollars on an average from unclaimed FSA/HSA dollars. The dollars go back to the company, whereas the employee actually paid towards this from their salary check.
We have to place a gamble each financial year and see our money lost towards the end of the year. We would be confortable seeing the money being taxed at the highest brack and returned to us. Even a flat tax of 25-30% is acceptable.