Soft Playing? Chip Dumping?

[donkeyradish]

From the pokerstars tournament rules:

Soft playing or chip dumping is grounds for disqualification from the tournament. Any unethical play may result in the termination of the offender’s account.

Can someone elaborate on what these terms actually mean?
There must be a world of difference between

1) Folding to deliberately let someone else at the table have some chips
2) Folding to preserve your own stack

While 1 is unethical, 2 is surely not.

Yet these actions are exactly the same. You could no more prove someone did 1) than you can prove they intended 2)

I have certainly been accused of 1 when I intended 2. Where do you draw the line?