Arts and crafts fairs tend to have fairly similar rules, and participants can get a bit fussy about them: Everything in the booth must have been designed and created by the artist whose name is on the booth (no manufactured items), the artwork in the booth must correspond to what the artist submitted on slides (no abstract paintings by an artist who submitted slides of figurative work, no sculpture for an artist who sent in images of paintings unless that person submits in separate jurying categories), exhibited items and chairs must stay within the booth (no impinging on walkways or other artists' spaces) and the artists may not engage in any "active solicitation of the public" (no hawking) or post signs that indicate a sale or potential discounts, exhibitors must provide their own liability insurance, all work submitted for jurying must be for sale, the artwork on display was all created prior to some specific date (no crowd-pleasing picture from 20 years ago), loading and unloading only takes place during scheduled times (no disrupting other exhibitors or the public) and vehicles are not permitted on the site, no music or videos playing in the booth (disruptive), the artist must be present at the booth for the entirety of the event (no proxies).
All these rules make sense, but they may not work for every artist. The everything-designed-and-created-by-the-artist rule, for instance, may not work for those who have assistants (or who use a foundry or print studio), and requiring that everything on display be for sale may work against the interests of artists who look to enter a particular piece in another show or who may have already found a buyer. Regular visitors to art galleries know that not everything on display is for sale. A "proxy" (someone other than the artist manning the booth) may be very useful for artists who have other commitments; an art dealer, for instance, is a "proxy" when taking visitors through a gallery exhibition and can do a very adequate job -- perhaps even a better one than the artist -- of selling artwork. These rules reinforce certain beliefs (artists create alone and fair visitors require their presence for sales to take place, for instance) but also set a certain tone for these events: The things you see in the booth were made by that person in the booth. People do like to meet artists, whether or not they buy anything directly from them, and artists find that developing relationships with prospective buyers does help make sales.
Bans on mood-setting music or videos that demonstrate the artist's technique would seem to go against the interests of exhibitors who, within the crush of hundreds of booths, seek to put their work in some context, although not everyone can be trusted to adjust the volume control to low. The rule that all pieces on view were created within the past year or two may rule out artists who create very slowly and do not produce a lot of artwork; however, it is unlikely that anyone has surveyed visitors to art fairs, finding that they refuse to buy paintings that aren't fresh off the easel. Newness isn't an artistic criterion, but the emphasis on it by show sponsors reflects an arguable belief that visitors want the up-to-the-minute.
Other rules sometimes can seem plain arbitrary -- the Palm Beach County's annual "Artigras" disallows the display of "ribbons or awards from other shows," as though an artist's past success should be hidden -- or overly broad. Many fairs describe themselves as "family-friendly." The Atalaya Arts & Crafts Festival announces that it is "an outdoor public event for visitors of all ages. Artwork must be in keeping with this atmosphere." Does that mean no nudes, no images of war, no social or political commentary? Family-friendly is also not an artistic criterion, and the lack of specificity leaves room for potentially quite avoidable conflict.