Sorry to say this, but if you are worried about what is "yours" and what is "hers" you probably don't get what being married is all about. I would recommend just not getting married if your money and your stuff has you this worked up.
I disagree with you. The poster from the referenced link above commented how he had $100/mo in take home after child support and alimony. This is about preventing that as well as removing any financial incentive to divorce after clearing her debt, which I feel is an approriate topic on a forum dedicated to early retirement through badassity where divorce is so frequently cited as one of the biggest obstacles to the goal.
To give this thread some more substance I've done some research and contacted a lawyer. In California (and probably most community property states):
1. Both of you need a lawyer. Seems like quotes are around $2k flat fee for the agreement per person, plus $1k for a review. I'm not sure if the review is necessary; we tend to avoid 3rd legal opinions at work.
2. Language interpreted as a financial incentive for divorce is not allowed in CA. Under this logic I assume it's equally not allowed to disincentivize divorce, but I don't know for sure.
3. From reading the prequestionaire it seems like other posters are correct; this is of most value to those who have separate property and liabilities worth keeping separate post marriage (Pension/benefits going to kids, etc.). The only thing one can do in a CP state seems to be to separate out things as "separate" aka "not common propoerty" prior to the marriage which wlil be exempted from the 50/50 pot split.
Note: #3 might remove another huge percieved benefit of a prenup - avoiding a costly divorce. Sure, with a prenup one already has the previous assets split out so avoid that fight, but everything you earned together is still on the table which in our case should represent most of our wealth.
It looks like the whole shebang will be about $4,000 which seems like it's expensive to insure a little over $50k at risk (~8%). (100k assets / 2 vs. keeping the whole 100k). In comparison, 5 year Greek CDS during the crisis peaked around 10%.