There is in fact a CAPTCHA to prevent anon logins from posting spam. I also have restricted the IP range to exclude those regions of the world that are probably not that interested in a Northeast US hiking site. When I relaxed the IP restrictions in response to a member from Scotland, all the spam comes back. So, unfortunately, I put the restrictions back. So what little spam gets through does defeat the CAPTCHA, and may include a human.
Members do not see the spam posts because all anon posts are set to moderated, and Dave or I have to approve (or delete) them. I can't remember the last time I approved an anon trail condition - but I do occasionally approve Lost and Found posts. As I mentioned above, I simply set the trail conditions to hidden... they are discoverable if you know how, and I can put them back, but I wanted to see who missed them
Looking at the Trails NH widget shows only 6 or 7 recent VFTT reports, and mostly they are from Trip Reports, and aren't even all trail conditions (like the Alligator Eggs on Wittenberg). Trails NH just scrapes the trail conditions and trip reports forums.
Paddle Park and Nature Photography have had zero traffic for years... but they require authenticated users, and so there is no spam.