I think it is a default option and one that I have left set.
From my reading of the text would suggest that if you take a screenshot(capture) won't cause/trigger an alert.
That said I can't see a case where doing a screen capture would cause an avast alert. If said capture was related to a website capture, I would have thought you would get an alert by the Web Shield before you took a screen capture. On occasion when checking sites reported in the forums I check it out, on occasion that results in a Web Shield alert and I do a screen capture on the Avast Alert window, but that isn't triggered by a screen capture but the act of visiting the site.
So I would agree it needs clarification.
