From what I hear when people give their reasons, wanting to be canon normally equals a) lack of imagination or b) fear that they won't be recognized.
BTW, tried out my costume today, and while I must say I looked smashing in it, I wouldn't go for such slippery material in my costume again. Because I was lazy, and frankly, didn't really think it would be a big deal, I didn't do much to secure the different parts of my costume in place. I got some double sided tape thinking that if it kept J-Lo's dress secure it would work fine on silk charmeuse and silk noil.
I am a big enough jedi to admit that was a dismal failure. So now I'm off to the local fabric store to buy snaps. I think they're the most discreet way of making sure nothing slides off or looks xxx-eyed after about half an hour of wear.