Just saw this article titled "4 ways to win frequent flier rewards" by Peter Greenberg on MSNBC.com

"Here’s my advice for redeeming your miles for the flights you want.
1. When redeeming miles for a flight certificate or for a flight ticket itself, always demand a paper ticket. Every airline will try to force you to take an electronic or e-ticket. Don’t do it. With a paper ticket, you have a more negotiable document. A gate or counter agent can process it at the last minute.
That paper ticket allows you to do something the airline will tell you isn’t possible — but the airline knows is possible: fly standby on a frequent-flier ticket. As long as you’re holding a paper ticket and you haven’t changed the city pairs (your originating and destination cities), or your flight numbers, you can take that paper ticket to the gate, show proper I.D., and as long as there’s a seat available at departure time, you’re going to get it. The airline reservations people will never tell you this. The frequent-flier departments will often go so far as to tell you you can’t do this.
Of course you can do this, as long as you’re flexible. Remember, a frequent-flier award is a contingent liability the airline would love to dispose of. The airline won’t do it at the cost of a paying passenger. But at departure time, at the gate, an empty seat has your name on it if you have that frequent-flier ticket. Just bring your bags to the gate. And unless it’s the day before Christmas, Easter, spring break, Thanksgiving or a few upcoming three-day weekends, you stand an excellent chance of getting on that flight, or the one immediately after it."

My question is, the conditions Peter puts on getting on the flight is 1. paper tickets
2.the city pairs have to be the same 3.not have changed the flight numbers.
I understand the first two, but I assume that the flight numbers for the flight you want would be different from your original ticket.

Has anyone done this? Any commment about flying standby would be appreciated.