I have no personal experience on a colleague whom I have witnessed committing fabrication and/or falsification. If there was, I am not sure if it was reported. If someone found out an incident like this, I am not sure if the witness will be confident enough to expose it. We're not very informed how whistleblowers can be protected. Also, people within the academic community tend to maintain their good relationship with their colleagues. So maybe on this level, maybe many are not motivated enough to cause conflicts with their colleagues who are fabricating or falsifying data.