If someone contributed to starring a sandboxed question, and just after the question got ~3 votes, they posted their answer and then un-starred the question. As intended, no further answers are allowed, which would temporarily make the starrers focus only on their answers and make them get more stars than usual. Is that an intended behavior or not? If not, how can it be avoided?
You are absolutely right, this kind of abuse is possible, however…
1. There are lots of kinds of abuse, and only a subset actually occur in practice. I suggest we address those that we have evidence are actually happening. As the system keeps a full history of when everything happens, if necessary it would be easy to investigate any report of this sort of behaviour.
2. A lot of the most damaging abuse is carefully chosen to not publicly make the perpetrator look bad. This particular kind would arouse immediate suspicion and I think is therefore very unlikely to occur in practice.
3. The best questions will probably launch quickly and decisively if we get to the stage of having a lot of activity here. Removing a single person's vote isn't likely to make much difference at that point.