My sister is nearly 25, she lives in London and we don't see her very often. Her DP is relatively wealthy and she is used to mixing with other relatively wealthy people and has always struggled a bit to keep up with their expectations for less money.
However, every year she invites us all down to London for a big birthday dinner and at the end of the meal when the bill arrives makes it clear that my dad is expected to pay! Given that their are usually at least 6 if not 8 people having dinner, the bill is always £150+, and she never tells him in advance that this is the plan.
Would I be totally unreasonable to this year when she rings to organise her dinner ask her if she or her DP is going to be paying and that if she guilts dad into paying I won't go?
(Just to add, DP and I have offered to pay a share of the bill before but my dad has refused - I think because my sister's DP never does and he won't take our money if the other guy won't even offer it.)