With no kids on board, your best bet might be the oldest of tactics: Act confused, saying "Sorry, officer. I thought I was out of the no-wake zone" or "Isn't that only during manatee season? It's manatee season? I had no idea!" The actual rule of the road, which the cop might gladly share with you, is that ignorance of the law is no excuse. But sometimes, if you seem nice but just dumb or naive enough, and also earnest enough, the cop just might give you a warning.