Copyright depends on how distinct a sound or piece of music is. No one can copyright musical chords because they are too basic. It goes the same with sfx, footsteps are very basic so if you get a very basic footstep sound from somewhere then no one can proove where you got it. However if you took a star wars spaceship flyby sound that is very distinct everyone would know where it came from. Lucas would definitely sue.

You would also get sued if you tried to resell a cd library yourself, but they can''t prove in a court how a person got there basic sfx such as wind, rain, doors ect.

DRINK GIN! IT MAKES A MAN MEAN-milk and cheese

You cant copyright a musical cord because it is a natural occurance of mathematics and physics.
You can copyright yourself playing any chord you want.

Same applies for footsteps, though what you said does apply.
I imagine if you ripped the counter-strike footstep sound, it wouldnt be hard for it to be noticed, would it?

Humongous record artists have been sued and paid out the nose for using such simple things as a bleep from a video game.

back in the 80s stevie wonder used to spend hours just getting the right hi-hat sound. (for all non musos or those not familiar with the drum kit, its a double cymbal sort of thing which is harder to explain than i thought...)
I''m not sure he could prove you sampled HIS hihat but I bet he''d be pissed nonetheless...
point about basic samples taken though.. just thought I''d digress a little.


Gobsmacked - by Toby Murray

I''ve written a software synthesizer that has a freeware version (fully working, just uses synth instruments not samples). You can make your own sound effects with it (I do) and I also have a free sound effects pack to download from my main website. The software is called noise station.

http://www.noisestation.com

http://www.treality.freeserve.co.uk has the free sound effects pack

I''ve come up with some really great thunder and explosions.

This could be a bit of a drag but you could make yor own.
I sampled my wind screen wiper from my car, it sounded like a balrog!!! ( the motor was bust)
I sampled my chair swiveling, sounded like an old door opening.

Electric screwdrivers/drills held near the pickup of an electric guitar sounds weird.

Starwars laser noises were apparently sampled from an air gun.

Like any part of game development its fun to play around and experiment (if you have the time) and you would own the copyright.