Yes, they'd get retracted if caught and be a black mark / destroy a career if someone did something like this and it was proven they intentionally faked it.

What often happens though is that the paper will get retracted but then the authors play hot potato in blaming different people for faking it and it turns into a whole mess where you don't always know (i.e. cannot prove) exactly who did the faking.

"Someone else faked it and I missed it, just like all the reviewers!!"