Should I photograph the venue empty or with people in it?

Yes, shoot it empty if you want the table, the light and the plate to read. With people only if the release is signed and the frame shows the room without covering the food. Hold a gap before opening for the empty room, and decide whether any service goes in a separate frame. The miss is shooting mid-service and getting the backs of heads, tickets and a plate you cannot read. The room folder brings the empty dining room and, if it was needed, one atmosphere frame where the plate is still visible.