I have tried it at Trump in Las Vegas and it worked for us. We were upgraded to higher floor, better suite with a view. It wasn't the penthouse or anything but the person checking us in didn't bat an eye at the $20 I handed him with my credit card. We had booked on PRICELINE even. We just smiled a lot and got chatty with him about what we were in town for, etc. When he asked for the credit card, I handed him the card and folded up $20 bill and asked if he had any complimentary room upgrades available. Worked for us but may also depend on the person checking you in.
