14 CFR 381.7: Advertising.

No operator of a Special Event Tour or agent of such an operator shall conduct, or cause or allow to be conducted, any advertising, solicitation or other promotion for a Special Event Tour unless:

(a) The operator is in physical possession of enough tickets for admission to the event to provide such tickets for a substantial number of seats on the tour; or

(b) The operator has entered into a written contract with an organization that is the distributor of such tickets or an organization that receives such tickets directly from the distributor (e.g., a bowl committee; football conference, league or team; concert promoter or arena; etc.), the terms of which provide for that organization to furnish the operator enough admission tickets to provide such tickets for a substantial number of seats on the tour; or

(c) The operator has entered into a written contract with another person or organization that has a written contract or series of written contracts with the distributor of such tickets or with an organization that receives such tickets directly from the distributor, the terms of which provide for that organization (the organization with which the operator has contracted) to furnish the operator enough admission tickets to provide such tickets for a substantial number of seats on the tour.