What's Fair and What's Not

I had a sleepover last night with my friend and we were hanging out, when her little siblings call and want to come over. They come over ALL THE TIME so we decided to say no. Not so long afterwards, she went down to her house to get cookies and her mom had to talk to her. She came out crying, saying that she couldn't come up if her siblings couldn't come up. That is SO UNFAIR in SO MANY WAYS! She is my friend not her siblings, and I get to decide who I want at my house, and I don't want her siblings to come up. And most of the time, she's just getting them to come up here so my mom and dad can babysit them pretty much. Like there supposed to , when they're not!!! I understand if my friend is grounded for doing something wrong, but not letting her siblings come up is not a good excuse for not letting her come up. She is my friend not her siblings.