We stayed at the Dolphin last week and did just that. We enjoy using valet parking, especially while on vacation. They charge you $10 per day and the charge starts at midnight (we asked). We checked out and had the valet bring our car around just to load the luggage and then had them re-park it and went to MGM. When we returned in the evening we just had the valet get our car and we were on our way. It was simple, and hey we had already paid for the day.