A 2000% increase in bandwidth use!
Having been trying to discover the source of high server loads and spiraling bandwidth use since 24th May, I finally tracked the issue down to this AVG scanner - it has caused a 2000% increase in daily traffic from my server on a reasonably small site. The site usually accounts for just 14GB/month but so far in June we're up to 300GB.
Even worse, the requests aren't to real pages and are all generating 404 errors - literally hundreds of thousands of them. I have had to turn off a custom 404 error page because of this to reduce what my Apache server has to do.
Fantastic. I didn't like AVG before this, but now I am going to actively tell my clients never to use it.