Once I got laid off via 1:1 call. Once I got laid off via a mass call with HR, they canned my entire department at once (300+ people). Once I got laid off via bulk bcc'd email because I was on vacation and missed the last-minute mass call with HR.

This has never happened to me, but I am absolutely 100% positive some companies just shut your access off, send you an email to an account you can't log into any more, and move on without a second thought.