My parents are away this Christmas and as we are housesitting for them we will for once have space to have all of DH's family over for Christmas lunch (10 adults, 7 kids), so have all been invited. Last year DSIL did Christmas lunch at her house and I helped. We were all tasked with bringing something, and whilst she did the main course, I did starter and Christmas pudding and brought champagne (well, prosecco actually) for Champagne cocktails. DBIL's girlfriend was tasked with bringing wine, but rang me at midday on Christmas day to say could I bring wine as she had drunk it all the night before. She promised to pay me for it but never did.
As a result, I have decided this year that instead of divvying up jobs etc, (which didn't work out fairly at all last year) that I will charge each adult £25 towards the cost, no charge for the kids, and I will do all the shopping, cooking and preparing, so all they have to do on the day is turn up, eat and drink. I thought this was quite a kindness, but DBIL's girlfriend has taken issue with this and I am struggling to get themoney off most of them up front.
We are by no means rich and it would cost me a fortune to do Christmas lunch for this amount of people, so I thought this was the fairest way. AIBU to think that this is fair?