Policy seems to vary with individual hotels, especially outside North America. Some allow you the option of eating in the exec lounge or the restaurant (eg, London Waldorf), while others (perhaps most) give you one or the other depending on whether you've been upgraded to the exec level.

As other posters have said, I don't think you can assume breakfast in the restaurant will be free unless you have coupons or have been told it's free. Best to ask before you eat.