This doesn't hold, since all local, state, and national laws must be adhered to by default. If a contest doesn't limit the number of entries, you're allowed to

This doesn't hold, since all local, state, and national laws must be adhered to by default. If a contest doesn't limit the number of entries, you're allowed to enter as many times as you'd like. "Cheating" has a specific definition and the definition doesn't apply here. The "spirit" of the contest is subjective. Perhaps the spirit of an easily gamed contest for me is to teach my children a lesson about math and strategy. Maybe it's to teach my kids strange ethical lessons. No one would be down voting or calling it unethical if the state lottery allowed you to enter as many times as you wanted for free and you kept entering.