Has anyone ever sold any miles from their frequent flyer programs? Is it illegal or against any policies? How would they find out? Is 1.6 cents per mile a good deal for a 100,000 miles?

Yes, it's against their policy.
Yes, they will find out.
No, they won't tell you how they found out.

Last but not least... if they find out before or during your trip, you will be asked to pay the walkup fare.

"At no time may AAdvantage mileage credit or award tickets be purchased, sold or bartered. Any such mileage or tickets are void if transferred for cash or other consideration. Violators (including any passenger who uses a purchased or bartered award ticket) may be liable for damages and litigation costs, including American Airlines attorneys fees incurred in enforcing this rule."
This is from AAdvantage Web site. All Airlines prohibit selling FF miles. Do a search and you will find stories of people who have obtained or used miles "irregularly". They could strip you of all miles and your membership as well. I would strongly advise against it.

Depending on who you sell the miles to I guess. If you sell miles to your close relative, I doubt if airlines would be able to flag such travel.

All it takes is one question.

I have never sold miles, but I have used them as pretty serious bribes. Hey, whatever it takes.

Please see also anyone acutally been caught by airline selling/bartering/trading an award? among lots of others of course.

There are other threads discussing similar questions also. Here's one example:
http://www.flyertalk.com/forum/showthread.php?t=380859

Someone was caught selling UA miles recently. Here's his story of Sold award, got in trouble.

It's also against FT policy.

Posts that condone illegal activity (i.e., buying and selling of awards, direct fraud upon any program) will be removed without notice and accounts subject to deletion! We're not the law, but we know where they are.

The consensus is that it is not really illegal but it is against ANY program's policies. If you go ahead and sell them, you should be really careful and have a story worked out with your counterpart, in case the airline suspects something. personally, I would not risk it.

If you only have 100k miles in a program, no status and don't care about lifetime elite, there's not much risk to you in selling. However, if you have 1,950,000 lifetime AA miles and are thinking of selling 100,000 AA miles, then it's probably not worth the risk.

There's not much chance that you'll get caught, especially if you work out a story the other person. How difficult is it to make sure the other party says the award was a gift? Also helps if they know your name so they can answer the question "Who gave you these 100k miles?"

And selling miles is certainly not illegal.

This has been discussed on FT many, many times.

You are correct that selling miles is not illegal in a criminal sense. It's not a felony, or even a misdemeanor.

However, selling miles is illegal in the sense that it is against airline rules. And condoning it is illegal in the sense that it's against FT rules.

From dictionary.com:

il�le�gal adj.
1. Prohibited by law.
2. Prohibited by official rules: an illegal pass in football.
3. Unacceptable to or not performable by a computer: an illegal operation.

Alright.

Selling your miles is still most certainly not illegal. Being against airline rules (or FT rules, as you seem to want to go there) is not enough to make something illegal. And yes, I read definition #2 that you pulled from dictionary.com. But I'm not sure if being on dictionary.com is enough for me.

From the OED:
"A. adj.

1. a. Not legal or lawful; contrary to, or forbidden by, law.

1626 [implied in ILLEGALNESS]. 1639 FULLER Holy War II. viii. (1647) 54 Gibellinus..concluded the election of Ebremarus to be illegall and void. a1654 SELDEN Table-t. (Arb.) 75 In all times the Princes in England have done something illegal, to get money. 1769 Junius Lett. xxxv. 166 They have set aside a return as illegal. 1817 W. SELWYN Law Nisi Prius (ed. 4) II. 925 Intended for carrying on an illegal commerce. 1855 MACAULAY Hist. Eng. xxi. IV. 605 To print such a tract without the approbation of the licenser was illegal.

b. Lawless, irregular. Obs. rare.

1728 R. MORRIS Ess. Anc. Archit. 20 How preferable the Beauties of ancient Architecture are to the illegal Practices of our modern Builders."

Find me something from the OED or Black's and then I'll reconsider.

That's OK but thanks for the offer to reconsider.

You seem intent on using a very narrow definition of illegal and that is certainly your perogative. However, IMHO, you are missing the bigger picture. The OP asked if selling miles was illegal or against any policies. Even if I concede your defintion of illegal (which I don't ) and answer "no" to the first part, the answer to the second part is still clearly "yes, buying and selling miles is against airline policy." As a wise FTer once said: YMMV

I don't think I ever said that selling miles was not against airline policy. I certainly would not have made the recommendations that I gave a few posts up had I thought this.

I also never asked that you reconsider anything (and I certainly wouldn't make you any type of offer). I simply said that I don't hold any stock in the definition that you pulled up on dictionary.com and that I would reconsider if you could produce the definition from either the OED or Black's. You can spare yourself the trouble though, as the definition in Black's is the same as definition #1 on dictionary.com.

So, to review for those scoring at home, the OP asked "Is it illegal or against any policies?" You then brought up the legality issue by quoting FT's TOS. You said "It's also against FT policy. Posts that condone illegal activity (i.e., buying and selling of awards, direct fraud upon any program) will be removed without notice and accounts subject to deletion! We're not the law, but we know where they are." To which I replied "And selling miles is certainly not illegal."

So, I stand by my statement that selling miles is certainly not illegal. If the OP is considering selling miles to a broker, the worst that will happen to him is that the airline cancels his account. If the OP is considering selling the miles to a family member or a friend, then there is nothing to worry about.

I will leave it at that as it appears the person that I am debating with is "good people" from TX/OK. Were they from MA/CA I'd keep at this for days. And I believe that we are in agreement that selling miles is not illegal but is against airlines rules. Over and out.