So basically the OP just gave you an example on social engineering.
Getting what you want by influencing other people.
By telling these people you were banned because of a problem they have that they made public, the false positives on their hackshield, they provided you with a doorway.
This is not fail at all.
This particular excuse may be used up so to speak, but it's only one of the limitless ways you could execute this.
They gave many others reasons why people were getting banned, use one of those as a base to start YOUR letter.
And don't forget, always be formal and use at least DECENT spelling and grammar.
Saying things like:
"i wan my accunt unban now plz, i not hacker, just virus scan."
or any use of "u" "ur" "plz, plox, plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz"
EXAMPLE:
Hello, while I was playing WarRock [DATE OF BAN] the game closed, and when I tried to re-open it, I was informed that my account had been banned, upon investigating the cause, I found that my antivirus software [Feel free to insert a name here, like AVG, throw in a version number if you feel like it] had placed the hackshield files into quarantine because of a false positive when it had scanned them. Since I did not violate any of the rules that would warrant a ban on my account, and have seen this same issue with others as well, I believe it only fair that my account be restored. I have restored the files to the correct places and instructed my antivirus to ignore the WarRock folder and all of its contents.
Thank you.
Be creative, be polite, and don't forget.
If you were BLATANTLY hacking or a GM saw, or you got banned for some other reason more severe, chances are nothing will work.