Kempis....If you just show up at the front desk you're at kind of a disadvantage. They're more likely to say that "we're over 75% capacity so you can't use that coupon." They know you're not likely to turn around and walk out. I just call ahead. Once in awhile the desk clerk will say that you can't prebook so I ask "well, how does it look as of now?" and they always say something like "it looks good."
Last week I booked ahead at a Hampton that didn't use roomsaver coupons and when I got to the front desk I managed to get a lower business rate. I got the lower rate AND the 2500 Hilton bonus. I wonder what would happen if you booked online and then handed them the coupon?