An honorarium is a payment for the contribution of a committee member. It’s usually not paid on an hourly basis. By definition it’s not considered to be payment for specific work.
And it’s paid in arrears. That is, it’s awarded to a committee member for past service.
So there should not be any expectation of future performance by that committee member.
It looks like this committee may be difficult to get a hold of. To me that’s a sign of a badly run scheme.