The probationary period has been used by bad employers as an excuse to screw over their employees for as long as working culture has been the cesspit that we know today. Many a manager has exhausted their encyclopedia of excuses simply to can somebody who the company doesn't want there anymore. This is especially true when the job comes with benefits—the health insurance and 401K combo doesn't come cheap (and can be used as an excuse to underpay you if you're kept on).
When one Redditor's mom and grandma worked at a casino together, they found themselves in exactly this situation. The company offered health insurance after 18 months of service, so they tried to fire most employees before they had worked that long so they could save some money. When the fateful time came for these two ladies, they made sure to give an exit to be remembered by. They deserved that last paycheck pronto.