There is an option to dispute if you think tumblr has wrongly banned one of your posts. I disputed every single "adult content" flag that I got on my vintage ad blog, and 30 out of 31 posts were restored.
NSFW images behind the cut.
This was an 80s ad found in New York magazine. The restaurant is still in business and now sells this image as a poster.
This was a 90s ad, maybe from Vibe magazine - when I originally found the ad, I was pretty shocked a mainstream (not adult / 18+) magazine ran it. I did not expect tumblr to "unban" this one, but they did
And then there's the naked varnish lady from the 1930s - everything else I've posted was eventually reviewed by a human and determined not to be "adult content." But THIS is the one ad that is actually 100% for real for real banned by tumblr.