My understanding is that the WARN notice does not apply when employees are terminated for cause. This has the extra "benefit" of not having to pay out unemployment claims.
For legal purposes, a separation letter for a for-cause termination must state the specific "cause" for which the employee is terminated.
Termination on the basis of poor performance (legally, "incompetence") requires supporting documentation, such as written reviews of the employees' performance prior to the termination. And legally incompetence only tests the employee's performance at tasks actually within their job description; an employee can't be fired for incompetence at other tasks. Very importantly, a new boss coming in and deciding that employees weren't performing up to his arbitrary (and new) standards doesn't pass muster.
A mass layoff for "performance" reasons has never been sustained by a labor department. The penalty is $500 for each day of violation (meaning each day short of the 60 required by the Warn ACT), plus all salary and bonuses that would have been paid during the 60 day period, plus legal fees incurred by the employees to protect their rights.
Additionally, a "for cause" termination on performance (or any other grounds) opens the employer up to per se libel lawsuits. Literally, all the employee has to do is submit a copy of the termination letter into evidence and they win unless Twitterlon can demonstrate that the employee was actually incompetent.
