Mo. Rev. Stat. § 407.023: Representation of a business at wholesale trade shows or markets — proof of agency required.

1. No person who alleges to represent a particular business at a wholesale trade show or market shall rent or lease space at the trade show or market unless he can produce written evidence of the agency relationship or contract status with the business he claims to represent; provided, however, that nothing herein contained shall apply to any trade show or market which in good faith endeavors to obtain evidence of said agency's relationship or contract status.

2. Any violation of this section is an unlawful merchandising practice.