I also just noted that the rack is on private property.

I wonder what the bike owner's home bike parking options are, he/she might live someplace that doesn't allow bikes to be stored indoors. That could be the only place he has to store it, which would also indicate that he lives within walking distance or rides mass transit or also car commutes and keeps the bike at work for lunchtime rides.

Just grasping at straws here until you get the back story on the bike owner.

Good luck on your quest.