Right or Wrong?

At a message forums that I hang out at a lot, but might I say, gotten very tired of it. The 'Terms Of Service' says ....
"Can not cover or obscure the banner advertisements on your personal profile page, or any Yuku page via HTML/CSS or any other means"

Would you say it would be in violation of that rule if someone used one of Firefox's adblock addon to block out ads placed on pages?
I'm kind of going both ways, right and wrong on this. You wouldn't be doing anything in the systems scripts page because the add ons are downloaded to your computer.