This problem affected Stack Overflow in its early days, and probably most beta sites are vulnerable to it. What can happen is:
- Subjective/vague questions get asked (as they always will be)
- They are often "bike shed" questions, that everyone has an opinion about
- For that reason, the answers attract a lot of upvotes
- Some early adopters who are keen to maximise their reputation like to take advantage of this, knowing that they can pick up thousands of reputation points from their answers to these questions.
- These same users are often the most influential, i.e. they are the ones discussing what the boundaries should be between on-topic and off-topic questions. But they do not want to close the questions that earn them thousands of points.
- When the site reaches public beta (and full launch), new users will follow the example of these influential users and post similar (bad) questions.
It took a very long time to clear the resulting questions from StackOverflow, with questions being closed/reopened/locked/unlocked multiple times (and worse, being migrated to programmers.stackexchange.com where they were equally unwelcome.)
What if anything can be done to prevent this from happening on a new site?
Related: Less discouraging presentation of closed questions for Beta sites