Sure, some would be lazy and some would cheat. They do that now. Most of us would honestly apply our expertise to doing the best job we could for our patients. That's what most of us entered medicine to do.
As insurance company representatives have told me, their contracts are to pay for covered services, and not to help people get well or to see that they do. It's just a business transaction, nothing more. For many physicians, medicine remains a calling and more than a business transaction. This is why we are so frustrated with contemporary American health care. We do care about people getting better and we would do what it takes to help them accomplish this if the decision making were in our hands instead of regulators.
In the United States, I don't see either political party untying our hands in any significant way. Both parties want to tell us what to do and to treat us as if they know best. What's lacking? Relationship, rapport, and the time required to listen, to understand, and to be helpful. I hear the argument that we would take advantage of the system. Then let's do an experiment and learn what happens. That's my goal to get a research grant to do this experiment as a demonstration project. To give some physicians a salary to care for a group of patients and to determine if they can do a better job for less cost than the current fee-for-service system that we have. Let's see if I get funded!