Davelias12:

Why should she forgo inviting the people she wants to come to her party in favor of SOs she doesn't know?

Because, speaking in generalities, the guests would be happier with this arrangement. Sure it is her party and she can do what she want but a good hostess makes sure her guests are comfortable.

As others have said, she is welcome to blow off the comfort of her guests, but she isn't likely to get many people to accept in those conditions.