The B-Team Bridesmaid... Second Choice Sucker?

A quick and dirty story submitted by the "B-Team" Bridesmaid:

My friend is getting married next summer. She and her fiancé are each going to have two attendants. I'm not one of the two she asked, and I'm perfectly fine with that. Attending a wedding is more fun as a guest! But then this weekend she tells me "Emily might not be able to make it to the wedding, so you might have to do it." 

Ok miss bride, two problems: 

1. You don't TELL your friends to be a bridesmaid, you ASK them. 
2. No one wants to feel like they are on the B-team. If I wasn't your first choice, I'd rather not be up there at all.

What do you think? How could the bride have handled this situation better?