IANAL, but here are a few thoughts:

- There's at least one example of a guy going through bankruptcy and keeping his miles:

http://www.cnbc.com/id/35823795/Home...Rewards_Points

(There may be threads somewhere about this article, which came out a few months ago)

- I imagine that the issue simply hasn't come up much for several reasons:

1. There probably aren't many people who have a meaningful number of miles and have filed for bankruptcy
2. Those people who do, have no incentive to disclose the fact
3. Airlines certainly have no incentive to get involved (any framework that gives a legal basis to mileage in bankruptcy could be the first step in the slippery slope to taxing them)
4. Creditors probably don't it worth their while to inquire because

a. Unlike financial accounts, court records etc, miles are not tied to one's SSN and there may not be even be a legal framework for airlines to respond to inquiries -- if someone going into bankruptcy change the addresses and then lie about having the accounts, what could the creditors do?

b. Sufficiently few people have enough miles to warrant the cost, and people have multiple accounts but only significant miles in a few ... a creditor could easily make over a thousand inquiries, on average, for every account found that justifies the effort

c. Miles can be illiquid. I suppose if a creditor knew of a high-mileage account, and the program offered cash or cash-like awards, the court could perhaps compel the person to get a bunch of gift cards and give them to the creditor, but in other circumstances it would be like bartering, and the illiquidity would make it impractical

So I would bet $20 that people keep their miles.
Interesting topic though.