I just downloaded the latest Adobe Flash Player 12 patch and without any prompts (except to say up front that the update includes security enhancements or fixes), it installed McAfee Security Scan Plus.
Instead of lodging a formal incident against Adobe and causing Adobe to waste time (I've already uninstalled the McAfee Security Scan Plus), I hope someone from Adobe sees this and stops this behaviour because it is annoying. There is already enough bloatware out there as it is. Otherwise, I will stop installing the latest Adobe updates and wait for n-2 because I don't know what I might find in them.
Also, please have the "Optional Offer" as exactly that; an optional offer to install McAfee Security Scan Plus. This means the checkbox to install McAfee Security Scan Plus should be UNCHECKED.
I would put money on the fact that they are being paid by McAfee for every install, not download. They don't care that they have pissed their customers off or that we are uninstalling the crap right away because they already have the cash.