I had someone who subbed, liked 5 pages of my novel, and left a sub-4-sub comment. I told them I wasn't going to sub to something if I had no interest in their project, but I did check out their novel for it would be fair, I think - they had a promising story. Yes, that person unsubbed and deleted the private comment on my dashboard.
I browsed their comment history; it was just a bunch of copy-and-paste. Thought it was a bot Tapas failed to prevent from existing, but it wasn't.
Never thought I would encounter one. Saddened to see this person go this route just to get a bigger number.