Standby and Airlines

[jmxthievez]

Hey guys, was just wondering what the official rule was for standbys? Usually I think it's from the same origin to the same destination you can try and go standby for an earlier flight, that's my understanding.

Yesterday, I had a buddy who was going from ny to chicago but connecting in DC, but went (and got) standby from ny straight to chicago. Is this a regular thing?

Also, is it possible to standby for a later flight? (risky)
Is it possible to standby for a completely different flight in terms of destination? What about similar destinations? like Newark, NJ to JFK, NY or something.

ty