Be sure to check the CCI website daily as June is normally when refunded tickets go on sale! I believe they mentioned it might be a “soft sale” where an announcement isn’t really made but it just “happens.” Basically, it doesn’t sound like there will be a warning.
If you want to be on top of things be sure to follow the CCI RSS feed, Twitter and Facebook accounts. I’d check the #SDCC tag as well on Twitter as I’m sure once it happens everyone will be tweeting about it.
I have a feeling a large number of passes were returned because of the hiccups experienced during the sale. I know right away I saw people talking about how they ended up with an extra pass here and there because they refreshed the page or thought they did something wrong. Unfortunately we really have no idea how many passes are returned and resold via CCI.
When they do go on sale remember to try and take your time! Don’t panic. You’ll want to make sure you enter all your information correctly. You don’t want to miss out because you typed your credit card number incorrectly. I know it’s hard but remember to just breathe and type with a steady hand!