The Arezzo cabinet is still stored in a dbc file. I have no idea if you can clean it from whatever dbc file it resides in, as I've never been in a situation where I've had to try.
I downloaded a lot from the Exchange yesterday that contained the Arezzo counter. There was no way to inform the creator that she has that virus (yes, I view it as a virus, because that's how it behaves), because her wall is set to Private and we aren't on each others Friends lists. Obviously I did not install that lot, but I wish there were a way to warn others that her lots now have that problem.
I don't think there's any other CC that behaves the way that counter does, fortunately, so as long as you avoid that, you're pretty much OK. That's not to say there isn't other bad CC out there; there is, they just don't tend to behave like viruses. I once downloaded a pair of boots that were categorized for all age groups - including infants - and that therefore caused some MAJOR issues in my game until I removed them. Made infants and toddlers look like bizarre giant spiders. The visual glitches sometimes even showed up in the town overview mode. But it was a .package file, so once I was able to narrow down the file, I was able to remove it from my game easily.
That is one reason that using CC in package format rather than sims3pack format is better. That and the fact that it won't automatically attach to anything you upload, meaning that even if you do use CC in a build, it won't get uploaded to the Exchange.
Speaking of CC, did you have a chance to clear the CC from your build, and try to upload it to the Exchange again? I'm betting you won't have any trouble uploading once you've removed it. :)