Here is a hypothetical situation. I am working with a small team (less than 5 people) on a project. While the project progress, we have some questions that we tried to solve, but for some reason failed. Then one of them post a question on SO.
Definitely for them:
This question shows research effort; it is useful and clear
(assuming it really shows effort to solve, but it is surely useful and clear). So they have high incentive to upvote it.
But this introduces a high correlation between upvotes from specific people and can be considered as cheating. But the users who upvote are not puppet accounts and are real people.
So the question is: is it a right thing to do?