We typically do a pot luck for a dish to pass and then the club foots the bill for brats and burgers. I tend to be the grillmaster which I enjoy.
I get to socialize with the club membership and other guests as it seems everyone gravitates to the cooking. We always have more than enough (smaller club), and invite guests like the Mayor, EC and some others to join us to see what it's all about.
I had a complaints about 2 people, one of which was not a ham and showed up with his ham brother. Apparently, he was the Joey Chestnut of South Jersey and thought we had a hot dog eating contest. LOL. I had to address it because numerous people complained. Otherwise as you said, we should have enough food for everyone.
The other complaint came from an indivdual who brought his kids to the Sunday breakfast one year. This event happened the year before I joined the club. Sounded like this individual only showed up to feed his family. I think the problem came when they ran out of food before all the ops had eaten, and when the ops showed up to eat, were vocal about the food being gone. And some arguments ensued. I am glad I was not there for that one.
As someone mentioned, you are going to get some of those types, no matter what. But it is a shame that it has to happen. Participation is as little as helping erecting an antenna, donating some time somewhere, etc.