I have never been involved in a research project nor witnessed someone commit a falsification or fabrication in research project so I cannot relate a personal experience. Nevertheless, falsification and fabrication can result to harmful ramifications and should be discouraged.
I would consider this a moral challenge if I ever encounter one in the future. It is going to be difficult calling out someone but I hope will have the courage to address this kind of action. If calling out personally is not going to work, I will make sure to report it to the institution as this might result in an incorrect and misleading findings that may harm others.
Being a whistleblower is scary so I hope the institution have a system in place that protects whistleblowers and to encourage people to be unafraid to report unethical research behaviors. When researchers are urged to police one another and will not be persecuted for reporting an unacceptable research act, there will be less incidents of falsifications and fabrications. As a new researcher, I will also be deterred from doing such acts because I understand the consequences, not just for me but for those involved in the research.