$20 "trick" recent results at LV Harrahs.

Pushed the wrong button. Will the $20 "trick" work in the Diamond check in, or is it better to try it at the regular check in desk>

The trick has worked for me in other diamond lines. Not used @harrah's, yet. Got a better hotel comp since, so I'm happily not in the S. LV Blvd zoo when I hit the ground. Thanks for answers, and Good luck!