What is the protocol for meeting a Dubai escort at the hotel lobby?

Most outcall bookings do not involve a lobby meeting. The companion comes directly to your room. She calls or WhatsApps when she is at your door. If you prefer to meet in the lobby, coordinate timing via WhatsApp. Sit somewhere visible and let her approach you. A brief greeting and walk to the elevator together is all that happens. Hotel lobbies are busy places where nobody notices two people walking to an elevator.