Staying at the opposite end of the country to where we live, with DH's parents. SIL and her DH have invited us all for lunch tomorrow. They live near to PIL. So there will be me, DH, PIL, and our 4DC. DH and MIL have informed me that we will call at Sainos en route to buy bread, ham, fruit etc to take, ie we provide our own lunch. For context, DH and I are comparatively well off compared to SIL. We are treating the whole family to dinner at a local restaurant tomorrow eve, including SIL and her DH, and whenever they visit us I cater for them very generously. So AIBU to expect that they can fork out for a few baguettes and some ham and cheese when they 'invite us for lunch'?