As much as I'd like to say you'd get caught quickly, you could probably get away with it for a while in any group that didn't have ML expertise already.
If you really wanted to you could fabricate results and in lots of cases nobody would be any the wiser unless you were supposed to be releasing software. Despite emphasis on peer review and repeatability, science relies heavily on etiquette. If you don't release code or a dataset a lot of times it's extremely difficult to repeat paper results, and that also means it's hard to disprove the work.
It's quite hard to get rid of incompetent people in academia, so I imagine you could get away with at least a year or two.
If you really wanted to you could fabricate results and in lots of cases nobody would be any the wiser unless you were supposed to be releasing software. Despite emphasis on peer review and repeatability, science relies heavily on etiquette. If you don't release code or a dataset a lot of times it's extremely difficult to repeat paper results, and that also means it's hard to disprove the work.
It's quite hard to get rid of incompetent people in academia, so I imagine you could get away with at least a year or two.