something like, “work out a date with your previous employer. We would expect the same.” The soon-to-be-former employee says they are resigning their position and says, “I’d like to start my new position around this time…” and then works together to find a good final date.
As for your assertion that companies do lay-offs without warning, that is disingenuous. Good companies provide severance packages. That buffer is the professional version of a two weeks notice, usually much better than two weeks.
@Sale - you could be justified in what you did. More context would necessary.