The Forest Service campgrounds around here have the "for sale" bundles of fire wood stacked against the trees at their site and not locked up. It's nice to camp in an area that is not worried about theft.
Locked up firewood would be the only reason I would need to "visit" the host.
If I was a host and if unlocking the door to the firewood storage area was a major part of my routine, I would probably consider an alternative method of providing firewood if i knew I was going to be gone for some time.