When I pay my mandatory dues to the Bar Association, the final total on the form includes a donation to the public relations fund. That is, the mandatory dues are ~$300 and total you are told to write on the check if you don't mess with anything on the form is ~$400.

I always have written the check for ~$300, but it doesn't bother me that much that they ask the other way. I think the public relations fund is probably a decent value for the utility it provides (if I could afford to donate at all).