No notice, no communication, nothing.
When I contacted the person at GitHub who did it he refused to answer any questions or explain anything.
So watch out... If you have the same name as an employee's drinking buddy, prepare to have your account removed without notice or explanation.
Sincerely,
the other rbishop
They have rules that after an account is inactive for a significant amount of time it is subject to removal.
I know this because I reclaimed a VERY inactive account. It had one repo that was forked years previously and never had any updates. And the user never contributed to any repos or anything. No activity of any type in years. So, I contacted GH support asking about the account and they removed the account and told me I could register it if I was fast.
I would very much hope that GH would attempt to contact the account holder before they deleted the account!
I was surprised how easy it was.
That being said, I would have gladly contacted the account holder but GH removed that capability a long time back. Instead I had to resort to the TOS rules that allowed inactive accounts to be removed.
IIRC, activity on private repos isn't exposed on the user's page. Is it possible for a non-employee to tell the difference between a truly inactive account and one that has activity on only private repos?