Autoblogs Violate Tumblr Guidelines
Stated very blatantly in the Tumblr community guidelines;
Mass Registration or Automation. Don’t register accounts or post content automatically, systematically, or programmatically.
Will My Tumblr Blog Get Banned?
Roll the dice. If Tumblr can prove that your blog is completely automated in nature, they could ban the blog. I don’t know if Tumblr would go to the extremes of checking all the app permissions and axing every blog synced with IFTTT. There are a lot of legitimate blogs that use automation. I do feel this gives Tumblr the ability to pick and choose.