Does anyone ever answer this question truthfully? I generally assume not. The only way to verify this is through a back channel (AIUI corps generally won't disclose the reason due to libel liability), unless the employee really screwed up and didn't sign a separation agreement, which (again AIUI) you'd only decline if you plan on pursuing legal action against your employer.

And if you're already on a back channel, then you don't care about playing fair.