The launcher (or minecraft) automatically updates files in your resources folder when it doesn't match what's expected.
I suppose you may be able to play with the file permissions so that you can read the file (to play it), but can't delete or overwrite the file.
Not sure what perms you'd need to accomplish that.
I'm pasted sounds from Minecraft 1.7.3. Then I launch the game and my sounds replaced to original Minecraft 1.2.5 sounds.
What is it? How fix it?
I suppose you may be able to play with the file permissions so that you can read the file (to play it), but can't delete or overwrite the file.
Not sure what perms you'd need to accomplish that.
But changing it like this will stop it from changing files that are already there.
You will download missing resources, but not changed ones.