Here's how I handle it in the States. If asked if I require late checkout, I'll answer either yes or no. When not asked, I don't say anything or request it. When and if they call me to check out, I'll just curtly reply with, "I'll check out by 4 pm. Is there a problem?"

After this year, I'm going full NY mode on all Hyatts Stateside. No need to be polite and gracious.