Still, I don't see that as "unacceptable" behaviour. It's something to be frowned upon for sure and it would be great if she could be punctual all the time, but being the CEO of an incredibly large and diverse organisation, she could be forgiven if she was late due to some other meeting or work-related issues.
Also, remember she's getting only about 4 hours of sleep everyday and practically lives at her workplace, so I doubt she's being late on purpose.