Need to vent-One of my cousins BMs in driving me nuts!

I am ready to have boucers at my cousins shower this weekend because I know there is going to be a fight. I am MOH and entire bridal party is chipping in for the shower. The problem is that her FSIL is a big baby who is always looking to cause drama. I was dealing with her in the beginning process of shower planning, but once we picked the restaurant, there wasnt much else to do until the day of the shower. I got a very cold email from her today telling me she feels like i put her in a 'time out' b/c she hasnt been involved in the shower. She works full time, has a 16 year old and a 6 year old, I highly doubt she would have liked to drive a half hour to my house at 10pm when i addressed the invites, or driven out to Tanger to pick up truffles for the favors. On top of it all, from the beginning, she told me she is a very busy person, I felt like saying, 'Who isnt busy?'
So, if I dont post anything this weekend, it means i may be in jail waiting for someone to post bail!!!!