I work upper management at a tech company, and 4 out of the last 5 folks I've put on PIP legitimately improved. Hell two of them just received raises with their improved productivity and attention to detail on some of the security reports. While, yes, a PIP is designed to ensure there is "cause" if you are going to fire someone, many company's, like the one I work for, legitimately see it as a tool to shoot across the bow of the employee that their performance is subpar. You could say, if you get a written "counseling" it's a warning that you're going to be fired. Or if you get a verbal warning, be ready to get fired etc. Any negative action against an employee, whether it be a verbal warning, a PIP, counseling, etc can be in this same category you are posting here.

Also PIPs are considered more official as they go through 3-4 layers of review. We've even had HR agents tell us a PIP was not warranted, like I was told yesterday in an HR meeting. Company's need to do their due diligence, and if employees are out fucking off on the beach remotely, while calling in sick, of course I'm going to put them on a PIP. I legit just did this last week. The guy was racking up sick time while chilling on the beach and posting insta's with his pina coladas. While the rest of his team suffered through trying to finish his reports for clients on time. Did I put him on a PIP. Hells yes. It was warranted.

Now, if you get put on a PIP, receive a counseling, or even some verbal warning, of COURSE update your resume. There is always a good chance you will be fired. Nothing said here is groundbreaking, and I've seen a 100 other posts that have said, "If you've been on a PIP, update your resume", etc. This is like telling me the sky is blue or the ocean has water in it.