Don't be afraid of "enforcement," be afraid of the site becoming low quality. When it comes to practical information, usefulness trumps inclusion in many cases. Think of the situation where you come to the site needing help with a problem. Do you want opinions and theoreticals (which you could get from random friends), or do you want practical advice from people who have actually taken on, and solved the problem in question?

Yes, we're all excited to be part of the beta, and yes we're excited to spread the word and get things going. No, we should not think that getting answers to everything is more important than practical information that people can use. If we find that too many questions are super subjective, we do the same thing as StackOverflow (or any other site): we vote down, we vote to close, we comment to give the OP advice, and we guide the community.

I think now is the best time to set the tone. I really think we should do this. I do trust voting, but voting isn't culture - voting is a person's opportunity to vote individually. Without a clear idea of what quality means, I fear it being watered down.

We should also remember that part of the purpose of the SE model is to make the internets a better place, not to simply create yet another community advice site without experts.