Oh the chair!!!! I SO know what you are talking about. Recently spent 5 days with my sister, her partner and his 2 kids camping over the easter holidays. My sister had travelled from WA so I knew I'd be supplying all the camping stuff. But is it too much to ask to stay out of my chair?! I bought it specifically for me cos it's comfy. So when I want to sit down, I want to sit in my chair. I kept getting eye rolls and the arhhh under the breath when I'd come looking to sit.
Surely it's not too much to ask that I sit in my chair, given that you are using all my other stuff (which I don't mind cos they cleaned up and did almost all the dishes etc).
It's the same at home. I have my comfy chair in the lounge and if you are sitting in it when I come in, expect to have to get up. In the end, noone really sat in my chair cos they knew they'd have to get up.
As for camping with other people, I have often gone with my cousin and her son. We bring our own food but often sit together to eat it. Sometimes we cook together depending on what we both have brought but generally we eat our own food. Over easter, the dinner meal was usually shared as there were so many to feed, it was easier to pool food.
And for breakfast, it's just put out all the cereals and everyone help themselves. We weren't always together at lunch so it was get your own. We all had a great time cos there was also two of my cousins and their kids there as well. Big family camp off it was.