GG and the wedding

I have a good friend getting married in September, this is his first (marriage) and his fiancee (her second marriage). This isn't about him, his girl asked me (Shauna) to attend the wedding, because she said I was beautiful and that Shawn was too brash.

I was honored, so I shopped and searched for the perfect dress, with all the correct accessories. This little shopping spree cost me a hefty $200.00, not only clothes but a professional makeup artist (only the best for Shauna). Now this is the best part of this little blog, she asked now that Shauna not to attend (halt) ahhh what did she ask?
Apparently she thinks that for some odd reason one of my friends which is her future husbands friends, will get a few drinks in himself and make a scene towards Shauna. Ahh my friends will make a scene towards me, I don't think so!
Now why would a GG ask me to a wedding and reception only to say a week later?

(mistake number 1)I showed her the dress and accessories before her decision and now I have to send it all back hoping to get refunded.What possible reason would she do that??

(mistake number 2)Don't invite someone and take back the invite just because you assume something may happen when you know damn well it won't.

That is one beautiful dress...I would have made a beautiful princess that night.