Having said that, given that many people do use separate GitHub accounts for their separate private and work personas, and many organisations seemingly expect their employees to do so, perhaps GitHub could consider revising this Terms of Service restriction to better reflect reality.

There have also been times when I would like to have access to a second GitHub account for testing purposes. (In particular, for testing GH behaviour when the accounts corresponding to PR commits, PR creator, and PR merger all differ -- see for example <https://github.com/isaacs/github/issues/1368>.)