I always think that option is a bad one (having it available that is), as I prefer to know what is going on, plus as you say there doesn't appear to be an obvious means of reversal. But I think that it only refers to just that instance and not all different files, etc.
I agree that having the option "Don't tell me about these types of files in the future" is bad. Three questions from this:
1.) If a user were to check this for whatever reason, how could they uncheck it WITHOUT using the Restore Default Settings option? Is there a way?
2.) If a user checks...."Don't tell me about these files in the future," would they still be submitted to the virus lab if Avast were to find something suspicious?
3.) If for some reason, a user choose not to participate in the Avast community, how would notification of suspicious files be handled? Note that participation in the Avast community should always be checked when the program is installed. This means that the instant Avast finds a threat, anonymous data is sent to Avast about it, so they can stop the threat with an update.
Jack