In an ideal working scenario, the white collar employee quits the second the PIP is issued.
Most white collar workers start job searching big time upon receipt of a PIP. A PIP unofficially ends most working relationships. The worker is either terminated for failing to meet conditions of the PIP or the worker finds a new job.
In my terminations, I was terminated by one job without any performance review. Another company gave me a poor review at a regularly scheduled interval performance review, then terminated me without a PIP. Both companies were pathetic excuses for actual businesses and I was glad to be gone from both of them.
A few years later, when I was cleaning out some stuff, I found that bad performance review. I urinated on one sheet of it and I pooped on the other sheet of it.