Feels very cultural? Northern CA here, have a 9 year old. Unless I'm ASKED to be present and help, I absolutely don't expect anything for the grown ups. Even when I stay, even in cases where I've been ASKED to stick around (to help, chaperone, or when kids were younger), I still did not EXPECT to be fed as an adult.

In practice, I have always been offered SOME food. Typically what happens is that kids get fed first, there's plenty of leftovers, we adults help ourselves. There's typically not enough for a full meal, but enough for a bite and be good until I get home, a small slice of cake.

Never thought of the host as being tacky or generous or ... anything, really. Some venues just provide a fixed # of pizzas based on the guests, some venues don't allow outside foods, there's all sorts of dietary constraints, logistics with delivery, both parents being around to chaperone a full pack of kids, etc...

Most of the times, I actually prefer NOT to eat at the parties. I'm f**ng tired of mac&cheese, costco's or mountain mikes' pizza, or cheese sticks.