Not subscribing to something not required for entering, does not disqualify a person.  You have to keep in mind that rules are as legally binding as a contract and have to be worded precisely, clearly, and outline what is and/or isn't required for entry and winning (although I've seen a lot of badly written ones with poor grammar and punctuation).  There are also laws and regulations governing the running of a sweepstakes/contests in each state that the sponsor must abide by.