Yep if I had not put my foot down it probably would have slipped by and never been noticed until some poor unfortunate PhD student tried to build their research off it.

Another anecdote - a certain famous professor (since dead) at my alma mater managed to destroy at least three PhD students careers via fraud. He had faked up the initial data and then put them to work on projects based on the fake data. The whole thing only came to light (internal only as it was all hushed up) when he died and his students moved to a new supervisor.