I really don't understand all of the comments saying BM's and MoH's just have to buy a dress and show up. There are expected duties and responsibilities that come along with that title.
https://www.brides.com/story/modern-maid-of-honor-duties
https://www.thespruce.com/the-maid-of-honor-3489936
https://www.weddingwire.com/wedding-ideas/the-ultimate-maid-of-honor-duties-checklist
Is it that crazy to expect that of people!? You ask someone to be apart of the biggest day of your life. If they can't handle the responsibility they need to turn it down. A GUESTS only responsibility is to wear clothes/buy a dress and show up!