<human>: So my family is having a very nice brunch. My wife and I had organized it, and before I had specifically asked my brother to chip in with me for my mom's meal. Everyone is having a good time when the bill comes. It's around $300 with tax and tip. 

My brother and sister think they only have to pay for my mom's and they had assumed I was going to pay for their meals. They make a big stink in public at the restaurant. My sister storms out saying that if she knew she had to pay for herself, she would've chosen a cheaper restaurant. My brother gets angry saying "it wasn't the agreement! I was only supposed to chip in for mom's. You never said I had to pay for myself too". 

My wife and I are shocked. We're wondering why they would assume I would pay for them on mother's day. I wonder if I had to specifically say, "pay for mom's AND your own". Sure, my wife and I are the successful money makers in the family (relatively speaking), but just because we do better, doesn't mean we have to pay for everyone else all the time. We had just taken the family out for my parents birthday last month and paid around $400. 

This, of course, upsets my mom and she was saying we should pay, then she would give my wife and I money to cover for my brother and sister afterwards on the sly so my brother and sister wouldn't be upset.

Reddit, should I have given in and paid for them? My sister is 34, unemployed and still lives at home without giving my parents anything for rent. My brother just got through 5 years of college, living very nicely off my parents generous allowance and has a job. I feel they should have known that they had to pay their own way at the brunch. This was for my mom, not them. Why should they assume I was going to cover their costs?

Can you give me a shortened version of the text?
<bot>: siblings assumed I was going to pay for their meal on mother's day brunch and got upset when I didn't. should I have just given in and paid?