Yes, data can be fudged, and folks do it all the time. However, that's contrary to the method (or doctrine).
Facts can not be made up. Messing with data, or coming up with fictitious data is an example of bearing false witness, or lying. One has a right to be told the truth. That's why the moral code forbids lying, bearing false witness, ect...
Fraud isn't contrary to the scientific method, only to the moral code. The logical operations of the scientific method will simply generate garbage if false data is used. ...GIGO.