1. Define kid. Later in the evening we realized there was a serious edge case; 17 year old couples. Do they count as kids? In the spirit of the rule, no. But maybe they were there with their parents and siblings and were actually 15. We'd need a definition of both kid and party before such a bet could be undertaken. Let's go with the loosest definition of party (just people who met, not necessarily came in the same car) and kid (anyone under the age of 18).
2. After that, I wouldn't think about it in terms of how much I'd be willing to bet. I'd think about it in terms of trying to determine what I thought a fair price was (just glancing around the restaurant I thought a fair price was something like 9:1 against there being another kidless party).
Proud of myself for explaining something, I sat back and sipped on my caffeine free diet pepsi (partyer that I am). Danielle simply restated her question, as is her custom and that of some other intelligent people I know after someone has explained that a problem is a lot deeper than what she originally posed, but also still very answerable. I thought about trying to discuss it in terms of the Kelley Criterion, but I assume that would have to be flawed as this is obviously an edge case. The answer to such a question relies on many things, all of which are inherit to a given person and therefore likely can't be decided with a formula:
1. How much money do you have?
2. How much money do you make?
3. How safe is that income stream?
4. How much money do you spend? Could you reduce it?
5. Will you kill yourself if you lose a certain number of dollars?
6. How old are you?
After thinking about these questions, and declaring that I thought the fair price of the bet was something like 9:1, I asked Danielle how much she would bet at even odds that we were in fact the only kidless party at the fine eatery. Her immediate response was....$500. I restated the question and this time told her not that I felt the odds were 9:1, that they actually were...simplifying the problem. You have an event that will happen with 90% certainty, and someone is willing to give you unlimited action at even money that it will not. How much will you bet? I managed to get her to say $5000, but that was as high as she'd go. Now I'm not going to go into her personal finances at any length here, but she does work at Google. That is all.
She wanted to know what my answer was, and after a few seconds of reflection I responded "I think all of it." She was stunned. Now I have money in a Roth IRA, and she argued that it's tax sheltered status meant I should never touch it, not even with a 90% chance of doubling it. And she might be right, I suppose. 30 years of untaxed growth is nothing to sneeze at. And I don't have a job, so betting every penny I could get my hands on would be perhaps a little silly. But even so, I think my personal answer is "the vast majority of my liquidatable net worth," and some of my answers to the questions above are decided "wrong." I don't have a job, and my income stream isn't very safe, specifically. Were I in her situation, I literally think I might bet every penny I could get my hands on.
So anyway, I thought that was interesting, and am curious as to what other people think. How much of your net worth would you bet at even money on a 9:1 favorite?