Listen up, avast: The discontent you see here is nothing compared to the thousands of users who aren't savvy enough to find this forum, let alone comb through it to find these (rather well-hidden) steps to disable this mostly-unwanted feature. I guarantee you those thousands are now simply planning to switch to another product at the end of their current subscription cycle, rather than tolerate a pop-up at every logon or research how to turn it off.
You should have learned from the demise of other AV products that decided to be perpetually intrusive: McAfee and Norton, once the grand dames of the industry, are now despised by virtually everyone for this very reason. I firmly believe that most of your current user base is people who came to avast as a REFUGE from obnoxious features like this. And I guarantee you will LOSE your precious market dominance within a year if you don't take PROACTIVE steps to detoxify the damage it has already done.
The feature needs to be disabled by default (at any install or update), and you should do this quickly. I bought my son a new PC yesterday night and was planning to buy avast for him when it arrives. Now I probably won't, because even though I know how to avoid the annoyance, I have no confidence that you won't dream up another.
Producing software that intrudes unnecessarily is the expressway to failure. Ignore this at your peril.