More than 1 in 4 workers earning at least $60,000 a year went without insurance in 2006, and such workers are too well-off to be eligible for medical assistance. They can, however, often wring tens of thousands of dollars out of hospital "rack rates" by going abroad for treatment. Estimates on the number of those who are leaving the United States for surgery range from an ultraconservative 5,000 to 500,000 annually if minor procedures are counted. Some employers and big insurers are so intrigued by medical tourism that they're beginning to look for signs that they should start covering it.