As did the OP, I preplan my stays. When I call to make reservations, I tell them I am using their hotel because I plan to charge, and ask if they can put a cone in the space before I come in. Most have a cone, all have been willing to save the place, and do if I call the day of arrival to remind them. I carry a cone with me and reserve my parking space when I am gone during my stay.
I understand ICE owners, driving around the parking lot, places all full, EXCEPT for those charging spots. Can't blame them.
And I leave my cell number on the dash as a common courtesy. No one has ever used it to harass me. I wish chargers had signage to remind anyone, even ICE drivers, to leave a cell number if they use the space.