I'm not sure how this works. If you earn achievements offline using the trainer, then will it show up when you're back online? And can they detecte if a trainer was used while offline?
Apparently they can. I'm not entirely sure how the setup works, but you can be banned for using the trainer in single player mode.
Even if you play offline, huh? Well, I'll add my voice to the concensus: This sucks.
Yes it does. If you read the article that they posted about this ([url]www.cheathappens.com/article_blizzardbans.asp'>Link) you can see actual emails that people have gotten from Blizzard about this.
[Edited by Bes, 9/8/2011 11:15:17 PM]