I have been a bridesmaid enough times to have been consulted for the movie 27 Dresses and to now put stipulations on my agreeing to be a bridesmaid(just kidding). I did jokingly tell my most recently engaged friend that I would decide whether or not I would be her bridesmaid after she picked the dress I would be wearing. Perhaps even worse than a bad bridesmaid dress is a bad date to a wedding.
I have never understood the need for people(girls especially) to think it's necessary to take a +1 just because the invitation said (and guest). I refuse to take dates to weddings, unless they are good friends with multiple other people in attendance(in which case they probably got their own invite).....or....well...that's it. I think it's even more inconsiderate when a person takes a date to a wedding and they are in the wedding party. There are too many obligations to pay sufficient attention to the person you take as a date. They are abandoned during picture taking, the entire wedding, the time between the wedding and the reception and they are often stuck at a dinner table with random other people they don't know, making brutally boring small talk. All this, while you are having a good time with your close friends at the front table. Would you want to be that date? Not me.
The only time I have ever enjoyed being some one's date to a wedding was last May at Steve and Anna's wedding. Again, I knew a large amount of the people there and have known Aaron for forever and let's face it, Aaron is a load of fun. Best wedding date ever.