@kaia Whether it's a real thing I don't know, but I think the point is the employee is not just leaving at a time that is convenient for them with no thought of the company's convenience, but is going out of their way to chose a time that's inconvenient for the company.

Of course, you can't let companies or people use their circumstances to compel work or employment. The solution is always for companies to treat the employees better, not rely on untrustworthy employees, and tie bonuses to performance at critical moments.