I suspect has something to do with this... probably more specifically tax regulations and "specific fiscal obligations"

In Spain, all prize promotions are submitted to the close control of the “Dirección General de Ordenación del Juego” (body of the “Ministerio de Hacienda y Administraciones Públicas”) and they are ruled by the “Ley 13/2011 de Regulación del Juego” dated 27/5/2011, that has amended and unified in a single text all the regulations on the subject of gambling and contests.

In Spain it is also necessary to observe specific tax regulations: also, prize promotions containing any elements of chance are subject to specific fiscal obligations, both at the initial stage of the promotion and after the delivery of prizes.