Additionally, there's a decent chance that if you show the hotel check-in agent your confirmation that states that it includes a free breakfast they will just give it to you. It's not like it costs them that much, and is an easy way to keep a customer happy. If the front-desk agent pushes back, ask for a manager.

I also would not ask "if your room includes free breakfast". I would take the presumptive close and phrase it like, "I have breakfast included in my rate. Can you tell me what time and where breakfast is served?" Then it's up to the hotel to correct it if that's not the case.