I noticed a similar change on my last stay at the Hilton Santa Clara. I've stayed here 50+ nights a year the last couple of years and when I arrive on a Sunday and the exec lounge is not open on Monday, I get a coupon for continential breakfast in the restaurant. I've always had the breakfast buffet and never been charged anything additional. But last time, I was told the coupon was good for up to $10 and I would have to pay the difference for the buffet. Maybe Hilton clamping down system wide?