actually in southern Ontario firewood can be a very scarce commodity, especially in the last couple of years with all the newbies that think a fire has to have 3' flames....I've not often encountered firewood "voluntarily" left behind, more often (particularly in parks) the remnants of failed fires in the pit.
But the rare times it is it has been a small and welcome offering. A small measure of etiquette I consider a strength of character rather than a weakness of mind. There is a paucity of the former and a glut of the latter particularly in these modern times.
On one ocassion I came across several dry poles leaning under an evergreen set back from the camp clearing. I hate now to admit this but I chose one to harvest for our evening fire, having no idea what they'd been for. Only afterwards realizing they'd probably been stashed for a winter camp. Ready-made support poles for canvas tents would be a boon in the backcountry. IIRC on a vid from HOOP he explains/demonstrates how a pole would weather better leaned just so rather than all cut and stacked. Fuel is never hard to find where I go if you're willing to take a walk in the woods. I usually cook over twig fires so it doesn't take much.
I've had times when collecting fallen, decent, dry wood has entailed a mile long trip upstream from any sites, as can be seen by the staggering amount of unburnable green trees cut down...