Regarding getting rewarded for doing the right thing: in an ideal world we wouldn't need to contemplate that because the reward would BE doing the right thing. Ideally we should expect alcoholics to have the wherewithal to quit drinking and pay for whatever treatment they need themselves; realistically health insurance is used to cover the costs of some treatment as a lower cost investment to save the higher costs of the ill social effects of alcoholism down the road. Ours is far from an ideal world, so if carrots as well as sticks actually get more people to take responsibility for their health vis a vis exercise and proper nutrition, I say let's at least look at them.
I am adamantly opposed, however, to classifying obesity as a disease. I think it renders the true meaning of "disease" meaningless, and it absolves people of their responsibility to acknowledge how they became obese.
Re current incentives: my employer (a county authority) has a really, REALLY neat one: the Sick Leave for Fitness policy. You can use the cash value of your accrued sick leave hours (calculated against your currently hourly wage) to be reimbursed for various fitness-related expenses, including gym memberships, fitness equipment (INCLUDING CATHE DVD'S), etc. In fact, I have been able to utilize this benefit to be reimbursed for the aerobics music CD's I buy routinely for my aqua classes. And, since it comes out of my hide and I'm taxed on it, the public really doesn't get dinged for it. Cool, huh?
a-Jock