When money changes hands, or it is bartered, that's a different story.

People to watch out for: coupon brokers, who match sellers and buyers of award tickets. It's a practice flies in the face of the rules of frequent-flier programs, which stipulate in strong terms that miles are for use by you and you only. (You're not supposed to even transfer tickets to your spouse.)

If you do go the route of buying somebody else's award ticket, be warned that if the airline finds out, it could easily confiscate it. Conversely, if you try to make a quick buck by selling your award ticket, and the airline somehow learns of it, it can close down your account immediately.

There are some exceptions. Air Canada, Continental, and Northwest are now allowing passengers to transfer unwanted miles into another person's account with the same airline. But there is a fee and limits on many miles you can actually transfer.

6. Funneling miles between different airlines will cost you dearly

The online agency Points.com through its contracts with different carriers does allow the exchange of miles between various frequent-flier programs. The catch is, they can only be moved among accounts that are actually registered to you. Even worse, you will generally lose a whopping 90 percent of the value of the miles in the conversion process to fees.

Industry analysts agree that this is usually not a wise path to take unless the traveler is absolutely sure she will never use the miles, or if the airline itself is in peril. In this event, for a business traveler, that extra cost to unload the miles may not be a big deal.

7. Keep tabs on miles yourself

With so many cross-promotions out there, it's sometimes to keep track of your miles' running total.

While hotels usually do a pretty good job of making sure the miles you earned for your room end up in your account, retailers can be downright negligent, since there is usually not the adequate infrastructure in place to convey all those miles from the store counter to your airline. At best, huge time lags will be involved, which could be disruptive to travel plans. Save all receipts, and give yourself a wide lead time before booking your reward ticket, to make sure you get the miles that are coming to you.

8. Besides miles, don't forget preferred customer perks

Miles, unfortunately, won't get you inside those comfy airport clubs that can be the only refuge of peace, quiet, and cleanliness in crowded airports.

Why? Airport clubs are separate revenue generators for airlines. They would rather stick you with an annual subscription than let you get in for "free."

Along the same lines, frequent business travelers may want to focus more on scoring "elite" status, based not on your lifetime flying miles, but how much you actually fly in one year. These tiered elite rewards can lead to seat upgrades--as available, of course--which for many harried road warriors are infinitely more valuable than any free trip to Tortola.

9. As currency, miles don't go far

Most airlines state it plainly; frequent flier miles are good for one thing only: airplane tickets.

For many travelers, that's too bad, because more creative uses for them would likely help to spend them sooner.

American Airlines is one of the few exceptions to the rule. In limited quantities, you can redeem your miles for rental cars and hotel rooms, which could be seen as somewhat ironic. While American is limiting the number of freebie seats on its flights, according to the WSJ report, the airline is also turning back the clock to the way its frequent flier system operated a decade ago, when these kinds of cross-redemptions were available.

For those travelers who just want some gift for all those thousands accumulated miles, this policy adjustment may come as good news.

10. It will get worse before it gets better

As some airlines continue their possible death spirals, they may become desperate to create revenue by any means necessary. That could mean more hidden restrictions on when you can fly, higher upfront fees, and more widespread raising of award levels.

Yet the ad onslaught continues. The Citibank AAdvantage card is currently offering 10,000 bonus miles just for signing up, while United is currently topping that with 15,000 sign-up miles. Yet however tempting, it's clear these miles are worth a lot less now than just a few years ago.

And the system doesn't seem like it will clue in travelers about how it works any time soon.

"There is no transparency, and that is what is outrageous about the whole system," says Winship of Frequent Flyer. "Consumers are totally in the dark about all this."