I think it is acceptible for a member of an organisation to question the CEO's salary when their fees are going to pay it.
It does seem that sometimes when people get into senior positions like this that they can abuse their positions (MPs and expenses for example) for their own personal gain.
But saying that, I understand that in a typical CEO position you don't work 9-5. You work whenever is required and the thing that matters at the end of the day is whether the CEO generates or saves more money than they cost.