This is a VERY excellent point, now that you mention it, and probably a near-perfect shortcut to evaluating how the employer supports the learning, growth & wellbeing of the employee.
The second job I left banned former employees from their offices after I attended a user group there (!!).
The third one paid for my goodbye lunch and invited me back for the epic parties.
I would have happily stayed at the third jobs for years, if they'd just let me ship ANYTHING without derailing it completely.