PJ -

Great discussion topic.  I have mixed feelings & behaviors re: the matter.

I'll admit to using log "furniture" when present & if it served my immediate needs.  However, my usual gut reaction is: I don't like to see it. 

In the old days, it bothered me even on peripheral lakes just outside of the park (ex. Three Mile Lake, just outside of Wolseley) when I'd see such structures all over the place in the extreme.  Nowadays, eager beavers seem all-too-anxious to make what THEY perceive as "improvements" well inside of the park, paying no heed whatsoever to park regulations and, more importantly, the aesthetics of the park.

In general, I probably have less of a problem with stone cairns than with log furniture.  Still, piling stones up still sticks "the hand of man" into your face just when you're trying to get away from that hand and INTO the wilderness. 

Bottom line: my general preference is to minimize evidence of the hand of man whenever possible.

My preferred response would likely be: inform park officials of campsites where I have seen such handiwork.  If I knew I'd have the park's blessing to tear stuff down, I might do it IF I knew I wouldn't further injure trees, etc..

That's my 2 cents worth, anyhow.

Jimbo   8-)