Honestly, the most surefire litmus test I've found is ex-employees who still speak positively about the employer. Conversely, a very vague non-answer, like "I

Honestly, the most surefire litmus test I've found is ex-employees who still speak positively about the employer. Conversely, a very vague non-answer, like "I couldn't really say" may hint at a non-disparagement clause in exchange for a severance package (with an NDA covering the existence of the agreement itself).