Anna, I am just seeing this thread and I see you are getting a lot of good advice. My two cents worth.
A friend and I were just discussing this last week. She said that she has family members who live right in the area where the reunion is who say, why should they pay to see the same people they can see for free? Of course they don't take into consideration they will be seeing people from out of state and people they may never get to see again. People have all kinds of reasons and we concluded most times it doesn't have to do with the cost. Some people just feel they shouldn't have to pay just because. Some come and intermingle and end up eating because there is plenty of food. At our last reunion in 2005, our daytime event was at a center on the main street in the small town and people were passing by on their way to the store there on the corner. My mother kept saying, "there's cousin so and so, he/she should be here or "That's Uncle so and so grandson, why didn't they come?" But that's a whole other story and topic. Some did stop and act as if they didn't know about it.
My cousins and I have come to the conclusion that it is not worth getting our blood pressure up. People are are they are, have been for 40,50, 60, 70 years. They are not going to change and you can't change them. It's all about what you can live with. I know that the committe members have spent a lot of time and have come out of their own pocket for extra expenses. You can choose to welcome them with open arms and allow for extra expense in your budget or you can have somebody by the door with a list and turn people away (like someone in my genealogy group did) and take the chance of bad feelings will occur or division. The bottom line, what is it you can live with and not get your blood pressure up. Again, people are who they are and they are not going to change.