[AFNobody]

Correct in most cases but if they put an identical job title out at an identical location, they are still vulnerable so you have to pick someone a grade more junior or a grade more senior to replace them.

[sjg007]

Or they work with recruiters.

[AFNobody]

Working with recruiters to hire the same position that was part of a layoff in the same calendar year is problematic for obvious reasons.