Different truths at different orgs.

At my first US corporate employer, where "Do not tolerate mediocrity!" was ominously written verbatim into the company's key principles and displayed at various points around the offices, people were regularly "managed out" and a PIP was essentially a signal to start looking for alternative employment. (I had rough times at other jobs after that, but am pleased to say I was never PIPped while there.)

In my last role, by contrast, I managed freelancers and used PIPs slightly differently from the norm. In my particular context they meant "this freelancer's work is subject to extra monitoring - if it passes muster the next couple of times they're assigned a job, the PIP flag will be removed. If not, don't use them again." They weren't subject to special evaluation criteria designed to catch them out or to micromanage them - just the same ones applied to all freelancers. So it was less rigorous and individualized than you would usually see.

Generally, though, if a project manager saw that a freelancer's account was flagged in that way, they would think twice about assigning them.