Dress at a bookfair, revisited

I was just reviewing my contract from the "new" Boston MARIAB book fair (Boston Antiques Weekend) . I know, I know, but while I am recovering, there is still an attorney lurking in the depths. Whilst perusing the document I ran across the following:

Dress: Business casual is required. No Jeans [sic], t-shirts, sweatshirts, or sneakers during show hours. ... Why a dress code? The Boston Antiquarian Book and Ephemera Fair is being produces in conjunction with the Boston Antiques Show. In the antiques show world, dress codes are common for better shows and since the Boston Antiques Show will be a high quality show, we must have the same standard for each of the shows.

So simple, so clear (so sad that there needs to be "Why the dress code?" section). I hope more shows begin to follow this lead. This is an issue that has been discussed ad nauseam by some here and elsewhere, and I look forward to seeing how this pans out. As I've said before, when you're asking the public to spend real money...dressing like you care is not too high a hurdle (not to mention a sign of simple respect).