So the post down the page a little ways about telling guests how to dress is making me wonder. Everyone was saying black tie, white tie, and venue requirements are the only time attire should be mentioned with regard to a wedding.
What about costume parties? I know they are not all that common, but I know especially around Halloween it comes up. Are costume weddings improper? Or is this one other exception? If this is not an exception, is it EVER proper to host a costume party? I would think the logic for a reception would extend to any party. If you shouldn't dictate attire for one party, you shouldn't for another. The fact that it's a wedding reception shouldn't change the etiquette rule. Sorry if I am way overthinking this.