Yeah I agree with you, I guess I just keep coming back to "make the punishment so eye-wateringly harsh very few people are stupid enough to try it."
Most types of fraud carry a $100-250k monetary penalty and up to 20, 25, 30 years in prison.
The number of people willing to fabricate research data decreases dramatically if you're going to have to pay the grant back from your $20/hr warehouse job after you spend the better part of a decade in a minimum security prison.