Yeah, response time might be slower in the middle of the night, but a falsified tweet on a celebrity account in the middle of the night is also likely proportionally less damaging.

Response time during lunch hour might be slower initially, but after responding to the first compromised account I don't think they'd be any slower.

If an admin account is only supposed to be for use by a human employee, it should have a rate-limit tripwire that automatically suspends the account and alerts the security team.