Usually I always avoided the lobby floor to avoid getting questioned when start filming elevators, unless that the elevator banks are hidden or not too close with the lobby or reception desk. I usually start filming elevators on the upper or lower floors where it is safe.
On the day I filmed the elevators in Grand China Hotel, I though starting and ending on the lobby was safest because I've also filmed the elevators in Mercure and Ibis Bangkok Siam (Two hotels in the same building), and started and ended on the lobby, but I didn't get questioned.
Maybe this is because the floors are locked in Mercure Bangkok Siam*, making they don't care at all. Hotel staffs in Thailand seem to careless when the floors are locked, as you still can't go up even you don't get questioned. Because of this, the hotel staffs let the keycard reader "took their job" of questioning unauthorized people instead.
*Although the top floor is unlocked because it's a pool.