So, I work for a Real Estate company, we sell houses ... many houses we sell are vacant.
Here is a story about such a house.
Once upon a time (as in yesterday) we listed a house and put a for sale sign up, no one lived in it, so we put on a lockbox so that agents, who have booked an appointment, could go view the house.
Then the lovely receptionist of the said real estate firm received a call, the conversation went like this:
Nosy Neighbour (NN):"I call about ABC house on DEF street"
Lovely Receptionist (LR): "Okay, I can have the agent paged he is not in the office"
NN: "No, no, I call police just now. I see two people I never see before go into house, I think breaking in"
LR: *exasperated* "That is an agent, with his client, he has authority to be there, the house is being sold"
NN: "No, I think bad person, bad person might set fire"
LR: *shocked pause*
NN: "The police just pull up, bye bye" *click*
LR: "Crap" *calls listing agent, can't reach him, 5 minutes go by*
Random agent who is showing the house: "Um, can you talk to the police and let them know I'm not breaking in ..."