Jane and Bob are brother and sister. Bob has a birthday coming up.
Jane decided it should be celebrated.
Jane and Bob both have two children who are the same age (early 20s)
In attendance is Jane, Bob, their dad, Jane’s children and Bob’s children.
Jane decides the bill should be split four ways. Herself, her dad and Bob’s DC1 & DC2.
Is it fair that Jane’s children don’t pay?
YABU - no they’re just as old and if they’re attending they should be paying too
YANBU - it’s Bob’s birthday and only his own children should pay