It seems that a malicious person A who has a strong dislike or enmity for person B's projects could do some real harm by buying upvotes/clicks/likes for person B's projects, getting them banned from various services.
Make it look like person B naively went out and paid a third party upvote/promotion service, and make it obvious enough to be noticeable.
to use some old internet terminology, make it look like a joe-job astroturf?