Sometimes the company ASKS you to take a package
A while back I quit a job and the company actually asked me to take a severance package. I didn't quite understand why they'd actually want to pay me to go to another job, especially when they'd countered with a rather nice raise and been refused. As my 2nd line manager explained over some brews after I'd left, HR just wanted to make sure I was covered by the covenant not to sue for age discrimination, disparagement, etc. Who was I to turn down over half a year's salary to not do anything I hadn't planned on doing? Especially since I wasn't annoyed by that company, just more excited by the new job's opportunities.
But seriously, anyone who posts something even remotely critical on something like Glassdoor without a VPN and a throwaway email account is doing it wrong.