If you're an Adsense publisher, you can surely understand arran's point in this WebmasterWorld thread:
When considering the TOS surely you have to apply common sense?
Scenario : I want to change my text color from 000000 to 000033.
Log into adsense, locate my template, make the color change, regenerate the code, copy it to my html.
Change 2 digits in my html.
Surely people with even basic knowledge of html are not choosing option 1.
I believe editing the code in any way does break the Adsense TOS. But in that case, I think about half of us have broken the TOS! Hopefully AdsenseAdvisor will speak up on the issue...